Add -rac_liftSelector:withObjectsFromArray:

Refactor -rac_liftSelector:withObjects: to become wrapper around
-rac_liftSelector:withObjectsFromArray.
Add -rac_liftBlock:withArgumentsFromArray:

Refactor -rac_liftBlock:withArguments: to become wrapper around
-rac_liftBlock:withArgumentsFromArray.
Extract lifting strategy into RACLiftAndCallBlock()

This change extracts the lifting logic common to -liftSelector and -liftBlock
into a single function.

Implemented as a static function to avoid needlessly adding methods to
NSObject.
Assert argument count in -rac_liftSelector:withObjectsFromArray:
Document *FromArray variety of lifting methods
Replicate method lifting specs for *FromArray variety

Copy the specs for -rac_liftSelector:withObjects: and
-rac_liftBlock:withArguments: and adjust to test the *FromArray alternatives:
-rac_liftSelector:withObjectsFromArray: and
-rac_liftBlock:withArgumentsFromArray: respectively.
Add method lifting tests around handling nil
Use @unsafeify over @weakify

For AppKit compatibility.
Correct format string types
Merge branch 'master' into lift-with-arguments-array

This merges in the changes from #424.

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa/NSObject+RACLifting.h
	ReactiveCocoaFramework/ReactiveCocoa/NSObject+RACLifting.m
	ReactiveCocoaFramework/ReactiveCocoaTests/NSObjectRACLiftingSpec.m
Follow array literal conventions
Make local copy of arguments prior to lifting signals
Merge pull request #438 from kastiglione/lift-with-arguments-array

Lift with arguments array