Fix frame client size in wxQT, thanks @seandepagnier

Compute frame size subtracting statusbar, and handle NULL status bar

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77914 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Allow NULL width and/or height pointer parameters in wxQT, thanks @seandepagnier

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77915 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Correctly handle default position values of -1 in wxQT, thanks @seandepagnier

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77916 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775