Merge pull request #38 from seandepagnier/SOC2014_QT

Fix memory leak and segv fault in dialog dtor

Thanks seandepagnier for the patch
Merge pull request #39 from seandepagnier/SOC2014_QT

fix memory leak/crash in wxFrame dtor

Thanks @seandepagnier
Remove Qt's libraries dependency from wxBase
Fix SIGSEGV on children destruction (frame and msgdlg)
Removed dummy Graphic Context in wxQT


If available, use Cairo like in wxGTK and other ports, but cairo qt surface not implemented yet.
implement wxToolBar from QToolBar
Merge branch 'SOC2014_QT' of https://github.com/reingart/wxWidgets into SOC2014_QT