Remove deprecated Q_WS_* defines that are removed in Qt5

All the Q_WS_blah defines are gone in Qt5. The Q_OS_blah macros are present in Qt 4.8, and probably earlier.

This pull request fixes all the occurrences of Q_WS_ that are in master right now. This will fix some mystery problems and compile errors that are occurring with Qt 5 on Windows, and everything should still work with Qt 4.