updating default behaviors

 - to check all setups are tested unless marked with DontEnforceSetupVerification()
 - to enforce setups are actually called by the production code, when marked with EnforceUsage()
fix existing tests

 - Now, they don't fail just because of the changed default behavior.
 - Setups were adapted so they would still behave as before with the new behavior.
Found new issue :

 - right now, we just added a new test to work around the problem. see Issue #15
Merge pull request #14 from Testeroids/IMockVerifyStartsCountingFromCallToBecause

updating default behaviors