Fix for small unnoticed mistake and add support for SenTest style failures

Fixed a small mistake in -[OCMConstraintTests testAnyAcceptsAnything].
And added support for SenTest style failures (eg: if an expectation was not fulfilled by the time verify is called Xcode highlights the line of the expect call as it would for an STAssert).

To enable this feature simply call -setFailureHandler: on the mock and pass it a custom failure handler or simply self (self referring to the SenTestCase)