Partial bugfix for issue 88: Final equals()-Methods should now work w. mockito



As requested here is the PullRequest for my suggested bugfix described here: https://code.google.com/p/powermock/issues/detail?id=88

I removed the usage of ObjectMethodsGuru as using it would have caused a dependency to mockito in the PowerMock core. 

The question that remains is if this fix is required, since the solution of using MockGateway.MOCK_STANDARD_METHODS = false; 
works as well. (But changes some more methods.)