Crash during virtual method call

[rmadsen-ks]

If parts of the call heirarchy does not implement a method, this can cause a stackoverflow exception to be thrown.

• StackOverflowException on calling super().method() pythonnet/pythonnet#2574
• Calling super().Method() throws an exception if its not implemented by the base class pythonnet/pythonnet#2629

[rmadsen-ks]

this was closed by #195