Added wheel support, adapted from https://github.com/marcusthierfelder/go-ui

(cherry picked from commit 88150f4139b4f9341162e0c6f399987bb1a0b20f)

Conflicts:
	README.md
	qtdrv/cdrv.cpp
	ui/cdrv.go
	ui/uiobjs.go
Added support for QWidget.winId().
Merge pull request #7 from whitelynx/mousewheel

Added mousewheel and winID support