Merge pull request #109 from akitchen/iOSDoublesAndHaveReceivedTestCoverage

Fixes up Doubles and HaveReceived specs for iOS and OS X
Fixes KVO compliance of CDRClassFakes

Previously setValue:forKey: would fail silently if invoked on a
CDRClassFake. This commit restores that behavior - otherwise we
throw a "class is not key value coding-compliant" exception.