If the user Alt-Tabs out of the window, we will be left thinking
the Alt key is still pressed since we don't see a release for it.
Solve this and other related issues for the nested X11 compositor
by selecting for KeymapStateMask which causes a KeymapNotify event
to be sent after each FocusIn, and when we get these events, update
the internal XKB state and send any necessary modifiers events to
clients.
https://bugzilla.gnome.org/show_bug.cgi?id=753948
MetaWaylandFrameCallback has been added a surface field, which is then
checked when destroying the surfaces. This prevents unintended callbacks
to run after a surface has been destroyed.
https://bugzilla.gnome.org/show_bug.cgi?id=745163
Add private functions for the test framework to use to find out the
wayland and x11 display names, so they can set up the environment for
children.
https://bugzilla.gnome.org/show_bug.cgi?id=736505
The initialization sequence before was quite icky, initializing Clutter
in a few different places depending on what was going on.
Put that all back into main.c
