Add $trim for NSString
Added  for NSString
Merge remote-tracking branch 'ericmeyer/master' into my

Conflicts:
	ConciseKitSpecs/Spec/NSStringConciseKitSpec.m
	src/NSString+ConciseKit.h
	src/NSString+ConciseKit.m

	modified:   ConciseKitSpecs/Spec/NSStringConciseKitSpec.m
	modified:   src/NSString+ConciseKit.h
	modified:   src/NSString+ConciseKit.m