[PyQt] Qt v5.9.2 Support

[Phil Thompson]

The current PyQt5 and related snapshots now fully support Qt v5.9.2. However I won't be making a formal release for 2 or 3 weeks.

There are some changes in the conversions of enums which means that invalid values can now raise an exception. If you are using correct values then you shouldn't see any difference.

PyQt has always ignored overflows when converting between Python ints and C/C++ integer types and the results of such conversions can be unpredictable in some cases. The sip module now implements enableoverflowchecking() which means that exceptions will be raised if a Python int is too large to fit in the corresponding C/C++ type. This behaviour will become the default in a future version of PyQt.

Phil