[Linter] Support for Gists.
[Linter] Support for Gists.

Closes #463.

vivekshukla-mob-ibtech/Repository,mglidden/CocoaPods,ashfurrow/CocoaPods,mglidden/CocoaPods,orta/CocoaPods,mglidden/CocoaPods,segiddins/CocoaPods,Ashton-W/CocoaPods,0xced/CocoaPods