Merge pull request #585 from dtsbourg/issue_492_scrollviewperformance

Rasterize collection view cell for scrolling performance, ref #492
fix #589. update insets when setting topContentAdditional inset
prevent cell tap delegate methods from being called with a nil indexPath. fix #586
fix composer text view insets. prevent single-line scrolling. fix #559
fix tests
remove FIXME for radar 18326340. issue has been resolved as of Xcode 6.1 ref #484
Update README.md
edit cell
fix auto layout constraint issues and warnings. set bubble width instead of margin. close #584, close #322
Merge branch 'develop' of https://github.com/jessesquires/JSQMessagesViewController into develop
fix issue where scroll to bottom fails until contentSize is at least a certain height. close #256
fix message hashes
fix scroll position #256
implement better message bubble size caching in layout for scrolling performance. #492
revert 4aedb06. close #597. cc: #484. sad face.
minor optimizations
minor optimizations
subclass text view to prevent unwanted text selection. close #591
verify outlets. close #604
expose cache countLimit. set default to 200. ref: #492