message: Added macro to enable assert on unexpected method invocation
  If FAKEIT_ASSERT_ON_UNEXPECTED_METHOD_INVOCATION macros is defined, an assertion is fired when unmocked method is called.
  This simplifies detection of unmocked method using stack track in debug mode
diff: @@ -21,6 +21,9 @@ namespace fakeit {
  void handle(const UnexpectedMethodCallEvent &e) override {
  fireEvent(e);
  auto &eh = getTestingFrameworkAdapter();
  + #ifdef FAKEIT_ASSERT_ON_UNEXPECTED_METHOD_INVOCATION
  + assert(!"Unexpected method invocation");
  + #endif
  eh.handle(e);
  }
  