Most of qt3 and gtk should stay compilable except for LyXView.h because the LyXFunc instance has been transferred to Application.
* frontends/Application: new class aimed to be the one unique interface between the frontend and the kernel. Contains one global pointer to the unique instanciation theApp.
* frontends/qt4/GuiApplication: renamed from qt4/Application, the qt4 specialisation of the Application class. Contains one global pointer to the unique instanciation guiApp (equal to theApp but pointing to a GuiApplication instead).
* frontends/qt4/lyx_gui.C: most of the code has been moved to Application and GuiApplication
All other file: adapted to new API.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@15114 a592a061-630c-0410-9148-cb99ea01b6c8
