Fix bug in autolink overescaping html entities

If autolink encounters a link which already has an escaped html entity,
it would escape the ampersand again, producing things like these:
    &  --> &
    " --> "
This commit solves that by first looking for all entity-looking things
in the link and copying those ranges verbatim, only considering the rest
of the string for escaping.
Doesn't seem to have considerable performance impact.
The mailto: links are processed the old way.

Extract a chain of ifs into separate func

This gives a ~10% slowdown of a full test run, which is tolerable.
Switch statement is still slightly slower (~5%). Using map turned out to
be unacceptably slow (~3x slowdown).

go fmt

Fix bug in autolink termination

Detect the end of link when it is immediately followed by an element.

Fix bug with overzealous autolink processing

When the source Markdown contains an anchor tag with URL as link text
(i.e. <a href=...>http://foo.bar</a>), autolink converts that link text
into another anchor tag, which is nonsense. Detect this situation with
regexp and early exit autolink processing.

Add a note about JavaScript injections to README

Rename HTML_SKIP_SCRIPT to HTML_SANITIZE_OUTPUT

Rewrite protection against JavaScript injection

This drops the naive approach at <script> tag stripping and resorts to
full sanitization of html. The general idea (and the regexps) is grabbed
from Stack Exchange's PageDown JavaScript Markdown processor[1]. Like in
PageDown, it's implemented as a separate pass over resulting html.

Includes a metric ton (but not all) of test cases from here[2]. Several
are commented out since they don't pass yet.

Stronger (but still incomplete) fix for #11.

[1] http://code.google.com/p/pagedown/wiki/PageDown
[2] https://www.owasp.org/index.php/XSS_Filter_Evasion_Cheat_Sheet

Extract useful code to separate func

Merge pull request #44 from FreakyDazio/safe-relatives

Relative URIs are considered safe

Merge pull request #43 from microcosm-cc/master

Cells in THEAD > TR are now TH.

Change GOROOT references to GOPATH in README

fix smartypants to pass single backticks through, issue #38

panic fix (issue #33) with test case

Merge pull request #32 from bertzzie/master

Enable Parsing Inside a Link

Merge pull request #31 from aybabtme/patch-1

Fix typo.

update license language to match OSI

Merge pull request #29 from athom/master

add EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK flag to make it closer to GFM

Merge pull request #27 from moshee/master

Footnotes (addresses #14)

Merge pull request #22 from rtfb/master

Add some protection against script injection

Merge pull request #24 from subosito/sample-fixes

Fix table syntax example on README

Merge pull request #16 from cespare/blockcodegithub_doc_fix

Fix up method documentation formatting for the BlockCodeGithub method.

Merge pull request #15 from moshee/master

HTML5

recognize fraction slash as well as regular slash to make fractions

link directly to blackfriday-tool

readme updates for go 1

updates for go 1

version bump to v1.1

permit backslash-escaped vertical bars in tables

fixed bug with blank line handling within list items

table unit tests and fix for a crash uncovered by them

bug in tables when a row has too few columns

tag as version 1.0

additional doc comments

doc improvements, commenting

readme tweak

readme updates

simplify naming of parsing functions

finished removing redundant end-of-buffer checks in block parsing; code cleanup

bounds checking stress tests

missing bounds check

removing more redundant checks, additional cleanup of block parsing

more consistent spacing of block-level elements

remove redundant tests for tab characters in parsing

remove NO_EXPAND_TABS options

removing redundant end-of-buffer checks in block parsing

move whitespace stripping to parser, not renderers

corner case spacing issue with table of contents

simplify inline callback interface

version bump to 0.6

inline helpers put parser arg first

Renderer is now an interface

preparing for switch to rendering interface

table of contents support beefed up

complete page rendering is now an option in the library

refactoring: inline renderers return bools, preparing rendering struct to become an interface

render -> Parser, made parsing functions methods of *Parser

camel case

added simplified interface for common usage

version number, few more options for command-line tool

example markdown binary: try to guess a title

options to supress tab expansion or to expand tabs to 8 spaces instead of 4

fenced code: ending marker must match beginning marker, tests for fenced code blocks

readme tweak

README tweak

simplified BSD license

preformatted html block tests

tests for ordered lists

horizontal rule and list testing

more robust whitespace stripping and matching corrections to tests

fixed minor bugs uncovered by more testing

unit tests for underlined headers, improved whitespace handling for the same

fixed headers nested in lists, added prefix header unit tests

eliminate a buffering level for paragraphs

clean up main markdown function: split out first and second passes

refactoring: newlines as hard breaks changed from HTML option to global markdown option

refactoring paragraph rendering

reduce copying for lists

experiment: render headers directly to output buffer to avoid a copy; minor speed boost

dumb tweak that gives a little speed bump

rewrite of attrEscape: cleaner and faster

enable profiling from command-line tool

fraction example in readme

more inline unit tests

output validates, command-line tool has useful options

improved (hopefully) smart quote handling

convert test files to unix format, fix a few broken ones

unit test for linebreaks

tab expansion bug

fix test name conflicts

Merge pull request #2 from kjk/markdown-tests

integrate tests for markdown 1.0.3 test files by comparing them with refe

starting inline unit tests, fix a few minor bugs they exposed

readme updates

comments, minor cleanups

rewrote the stinking pile of code that was blockParagraph

tab expansion fixed to handle multibyte unicode characters

gofmt

allocate new buffers on stack; mild speed improvement

export all names from Renderer struct
This enables new back-ends that are not part of the package
Basically a big search-and-replace for this commit

performance fix: with autolinking on, it is almost twice as fast now

remove dependency on less function

readme tweak

rudimentary latex backend, additional cleanup

split parser into multiple files, clean up naming

cleanup in markdown: better naming, misc fixes

comments on performance

fix smartypants and html entity escaping

escape entities when using smartypants

return result instead of taking buffer as input

features list

mdash

readme file

refactored into a proper package

smartypants

cleanup

compatibility fixes

output matches upskirt for markdown test suite

fixing link parsing

basics working, still a few renderers to write

parsing done but untested

working on inline parsing

emph parsing

reference extraction

setup, starting reference handling

fixed ordered lists

all block-level parsers

working on listitem

initial commit

integrate tests for markdown 1.0.3 test files by comparing them with reference files rendered with upskirt (no extensions)

Add some HTML5

HTML5 doctype, Wrap TOC with <nav>

<nav> makes the TOC more easily identifiable and workable with CSS.

Fix html tag ordering in doc string.

Fix up method documentation formatting.

fix table syntax example

Improve html element stripping code

Fix typo

Add HTML_SKIP_SCRIPT to MarkdownCommon

Couple more tests

More <script> stripping

Partially addresses issue #11.

Add an option to strip <script> elements

Partially addresses issue #11.

Make isHtmlTag() case insensitive

Extract repetitive code to a func

Fix bug in isHtmlTag()

Fix what seems to be a typo. j should iterate through all tagname, so it
should be initialized to zero. The test exposes this bug.

Make a way to parameterize inline tests

Expose extensions and html flags parameters so that tests could specify
what code paths they want to exercise.

parser no longer returns prematurely from empty footnote ref

leftover debug stuff

added slice bounds check

Implementation and some tests for inline footnotes. Also I noticed the list items had the wrong ids, that was silly of me.

Referenced footnotes appear to be functional. Inline still unimplemented.

new tests pass but old tests now fail...

First attempt at supporting Pandoc-style footnotes. The existing tests have not broken but the new functionality does not work yet.

add testcase for GFM autolink

make autolink peforms like GFM

add EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK flag to make it closer to GFM(Github flavor Markdown)

Fix typo.

Image inside a link now works.

Added test for link inside image

Updated tests to check for th tags instead of td tags within thead blocks

Added th to table headers so that styling with things like Twitter Bootstrap and typeset.css work as expected. Cells in headers should always be TH unless they are advisory cells within headers in which case TD is acceptable (but being Markdown a user with such needs could just enter HTML for this)

Tests for links when using  HTML_SAFELINK

  Relative URIs are considered safe