Add support for SetupAnyArg and VerifyAnyArg

We use Moq a lot in our team and I find that I spend a lot of time writing the correct It.IsAny<T>() parameters for Verify and Setup methods. I really wanted a simple way match any parameters and created two methods SetupAnyArg and VerifyAnyArg. When they are used, the underlying logic ignores any expression parameters and just matches the method by the signature. 

I realize that my current implementation might not be up to the standards of the Moq code-base and maybe I missed some important design principle. If you are interested in integrating this feature, give me some comments and I will gladly make the adjustments.