[WIP] Allow to decorate class with mock

Now it is possible to mock not only a function but also a class:

  class TestClass(object)

    def test_func_a(self, m):
        m.register_uri('GET', 'http://test.com', text='data')
        ...

    def test_func_b(self, m)
        m.register_uri('GET', 'http://test.com', text='data')
        ...

This new behavior mimics behavior of `patch` from `mock` library.


I would like to get your feedback on this patch. If it's OK, I'll add a docs.