gl-renderer: Use eglSwapBuffersWithDamageEXT when available
Add a fullscreen shell protocol
Generate/build the fullscreen shell protocol files
Add a signal for when a seat updates its capabilities
Add a wl_fullscreen_shell implementation
simple-shm: Add fullscreen shell support

This makes simple-shm act like a very simple fullscreen shell client.  This
is the kind of interaction one would expect out of a boot splash screen or
similar.
compositor-wayland: Add support for running on top of wl_fullscreen_shell
compositor-wayland: Add a --sprawl option

This forces weston to create one output for every parent output.  This is
enabled by default if it detects a wl_fullscreen_shell.  The --sprawl
option is primarily to enable this on wl_shell.
Automatically select the wayland backend if WAYLAND_SOCKET is set
Properly handle running inside a compositor that does not provide keymaps