* QWorkArea.[Ch] cleanup:
- Added private members workWidth_ and workHeight_ in order to
make sure QWorkArea is always able to draw (link to
workArea::WorkAreaResize).
- deleted superfluous debugging stuff
- deleted superfluous commented out code.
- placed all specific stuff (Qt-immodule, X11 and Mac OSX) in a
separate place at the end of QWorkArea.C.
- initial support for Wheel mouse (still does not work).
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@13348 a592a061-630c-0410-9148-cb99ea01b6c8
