toplevel: don't defer initialization when not in X11
gtk, toplevel: frame extents are supported only when running in X11
gtk, toplevel: don't crash when setting fullscreen outside X11

Only use internal X11 display if we're running in a such environment.
gtk, window: don't use X11 only functions when not in X11
Merge branch 'master' of https://github.com/wxWidgets/wxWidgets

Conflicts:
	src/gtk/toplevel.cpp
Merging with trunk
glcanvas: first experimantal version using GtkGLArea

FIXME!! Currently broken, but it's something we could do.
Merge branch 'master' of https://github.com/wxWidgets/wxWidgets