Add tests for [NSInvocation mkt_retainArguments], especially that it should not replace the target on a second call

https://github.com/jonreid/OCMockito/issues/67
Add -reset method to mocks to forcibly clear retain cycles if SUT is not being deallocated

https://github.com/jonreid/OCMockito/issues/67
Update Travis xctool and use with iOS 7.1