[PyQt] SIP Support for wchar_t

[Phil Thompson]

As of tonight's snapshot SIP has support for wchar_t. There are some issues 
related to wide strings and the heap - see the documentation for details - 
which could be partly addressed with some new annotations. I'd prefer that 
any changes are based on real world examples, so let me have some feedback if 
you use want to use wchar_t in your own bindings.

Phil