Extract category_link filter from category_generator.rb plugin

Allows category_link to be used as a filter to display a link to
any category.
Raise RuntimeError when gist is unavailable
Convert to integer before comparing. data.code is String
Fix for bottom margin in nested lists.
Add EditorConfig file for Ruby files
Add EditorConfig file for classic theme
Added robots.txt, with sitemap link
Added stringex and changed to use #to_url for create directory. To don't receive error in url to accented characters.
optimized order of styles and scripts in header
Updated Github API to V3.

Github API V2 has been removed.  The response data format also changed.
Updated Github API to V3.

Github API V2 has been removed.  The response data format also changed.
Fix for issue #622

The filters bundled with Octopress are not applied to files ending in 
`.md`, because the match in octopress_filters.rb does not match `.md`.
Merge pull request #706 from Confusion/patch-1

Fix for issue #622
Merge remote-tracking branch 'upstream/master'
bumped rbenv version fixing #743
Merge branch 'master' of github.com:imathis/octopress
Updated Github API to V3.

Github API V2 has been removed.  The response data format also changed.
Updated Github API to V3.

Github API V2 has been removed.  The response data format also changed.
Merge pull request #675 from zlu/master

Update Github API to V3
Twitter API call and links are now protocol relative