Add -[NSObject rac_description] for faster descriptions
Replace many calls to -description with -rac_description

Mostly on objects where the class is unknown.
Imitate rac_description in NSNotificationCenter+RACSupport
Add test case for NSRange returning method lifting
Add lifting support for NSRange

at NSInvocation -rac_returnValue.
Added comments
Merge pull request #489 from ReactiveCocoa/faster-stream-names

Skip full -description for some values in stream names
Add a RACSequence enumeration test that overflows the stack
Honor the length in RACArraySequence fast enumeration
Fix integer underflow in index arithmetic
Merge pull request #494 from ReactiveCocoa/fix-array-enumeration

Fix stack clobbering in RACArraySequence fast enumeration
Receive as NSValue * instead of id

and we can use dot syntax.
Merge pull request #491 from kkazuo/supports-nsrange

Supports NSRange for NSInvocation -rac_returnValue