add target blank attr
add nofollow ref for non internal links only
test: add nofollow ref for non internal links only
Use go.net/html's parser to sanitize HTML.

Use an HTML5 compliant parser that interprets HTML as a browser would to parse
the Markdown result and then sanitize based on the result.
Escape unrecognized and disallowed HTML in the result.
Currently works with a hard coded whitelist of safe HTML tags and attributes.
Merge pull request #69 from mprobst/master

Use go.net/html's parser to sanitize HTML.
Allow rel attribute in sanitizer

Fixes issue #68.
Merge branch 'master' of github.com:gihnius/blackfriday into gihnius-master

Conflicts:
	html.go
	inline_test.go
Merge branch 'gihnius-master'
fix: Handle all different token types that the parser can emit (d'oh).
Merge pull request #70 from mprobst/master

fix: Handle all different token types that the parser can emit (d'oh).
Add support for a bunch more safe HTML element tags, and bring them into some order.
Merge pull request #71 from mprobst/master

Add support for a bunch more safe HTML element tags, and bring them into...
Add some more HTML tags to the whitelist.