Ignore protocol relative '//' urls.
Removed accidental call to expand_url
Fixed the expand_url filter. Finally.

Thanks @larryprice
gist_plugin: Handle multiple redirects, stopping if we find a circular reference
Merge pull request #1506 from duckpuppy/handle-multiple-redirects

gist_plugin: Handle multiple redirects, stopping if we find a circular r...
Merge remote-tracking branch 'octopress/master'