Record/Replay improvements

[nirizr]

The following items are nice-to-haves now that basic record/replay functionality is in.

• replay multiple files in a single test run.
• support replay for python 3 although record was done with python 2.
• support external execution from python 3 although IDA instance runs with python 2.
• Proxy classes themselves to get class attributes This seems unnecessary for now.
• return correct class proxy for __class__ attributes. This seems unnecessary for now.
• support __subclasses__, __bases__, __mro__ and the likes. This seems unnecessary for now.
• Selecting the proper callback recoding (if more than one) in function callback replaying?
• Include a test identifier (such as test name or index) in "instance_desc" dictionaries.
• catch replay exceptions for missing attributes or key dict names and translate them to the correct record meaning.
• Fix remaining issues with instance matching for instances involved in callbacks.