Delete prefix header.

They're so passé.
Delete old CocoaPods junk from xcodeproj.
Replace Awful Browser with a shiny third-party thinger.

Also CocoaPods bumped to 0.35.0 so there's presumably some faffing about there.

This is actually a modified version of DZNWebViewController. Those modifications are submitted upstream as pull requests 11, 12, and 13.