Refactor OmniAuth configuration and fix it with 37Signals.
Add the font-awesome-sass gem.
Turn authentication links into pretty buttons.
Use FontAwesome glyphs for asc/desc arrows.
Enable download of user credentials.

Closes #529.
Improve docs for ForecastIO in WeatherAgent
Upgrade ffi to 1.9.4, and remove platform conditionals.

Specifying a released version of a gem as requirement wouldn't hurt
other platforms.
Merge pull request #538 from knu/refactor-omniauth-providers

Refactor OmniAuth configuration and fix it with 37Signals.
Merge remote-tracking branch 'knu/font-awesome'
Merge pull request #541 from knu/download_credentials

Enable download of user credentials.
Merge pull request #545 from mozz100/master

Improve docs for ForecastIO in WeatherAgent
update to newest json editor