Spy handles unresolvable methods as original class

Some framework classes, like UITextField have methods like
isSecureTextEntry which have no implementations and aren't forwarded (at
least on iOS <= 6.1).

This change makes CDRSpy fall back to performing the invocation with the
object as it's original class.  Whenever this happens, messages sent
during the execution of this message won't be recorded.  That's not
ideal but hopefully this will only happen in obscure cases like above.
Fixes up Doubles and HaveReceived specs for iOS and OS X

- Doubles and HaveReceived specs are once again run when testing on iOS
- Required changing primitive types and format specifiers used in specs
  to be valid in both environments

[fixes #54323400]
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.
Merge pull request #110 from akitchen/CDRClassFakeKVOCompliance

Fixes KVO compliance of CDRClassFakes