add mock.Reset() method. Support reverting a mock to clean state.
1. Rename Verify(mock[&func]).Times(x) to Verify(mock[&func]).Exactly(x)
2. Use quantifier on Verify(mock[&func]).Exactly(X_Times)
                     Verify(mock[&func]).Exactly(1_Time)
                     Verify(mock[&func]).Exactly(Once)
Merge branch 'master' of https://github.com/eranpeer/FakeIt.git