more tests for property subscribing
refactor the KVO wrapper to fit better with KVO signals
more tests
lazy KVO signal
document the block type
array instead of a set
varargs
slightly more documentation
style
just conditionalize the nil case
don't include the KVO whatnot in the iOS headers
Merge pull request #289 from github/lazy-kvo-signal

Lazy KVO signal
Call class_replaceMethod with deallocMethod's type encoding in
-rac_addObserver:forKeyPath:options:queue:block
Merge remote-tracking branch 'origin/master' into fix-superclass-dealloc-swizzling

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa/NSObject+RACKVOWrapper.m
	ReactiveCocoaFramework/ReactiveCocoaTests/RACKVOWrapperSpec.m