Reset unmatchedRequests during Off()

[Nikolay Turpitko]

I think, it could be nice to reset unmatchedRequests during Off() so that unit tests will be more independent of each other.

[Tom]

In gock@v1.0.5 you can now use: gock.CleanUnmatchedRequests() or gock.OffAll(), which behaves like gock.Off() + gock.CleanUnmatchedRequests.