Added RAC support for UIImagePickerController.
Style fixes.
Updated project settings for header, added import to ReactiveCocoa.h.
Added test for functionality.
Removed dismiss code out of category, added note about dismiss responsibility to header.
Style and import fixes.
Added signal for picker cancellation.
Changed reduceEach to mapReplace, added blank line after cancelled signal, separated test for picker cancellation
Changed takeUntil: for imagePickerSignal.
Changed condition of second test to beNil().
Updated header doc removing statement about nil on cancellation.
Backport reimplementation of -aggregate: from 3.0-development
Minor code style fixes
Use dot syntax
Merge pull request #1270 from ikesyo/backport-aggregate

Backport reimplementation of -aggregate: from 3.0-development
Rename block parameter of -scanWithStart:reduce:
Add -scanWithStart:reduceWithIndex:
Steal documentation for -aggregate: from 3.0-development
Add -aggregateWithStart:reduceWithIndex:
Add failing test for KVO bug