compositor-wayland: Add fullscreen support

This adds fullscreen support to the wayland backend.  You can make any
output fullscreen by the shortcut CTRL+ALT+F.  You can also run weston with
the --fullscreen option which causes it to create a single fullscreen
output.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
diff --git a/src/compositor.c b/src/compositor.c
index de113f1..2ca73d9 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -3700,6 +3700,7 @@
 		"  --width=WIDTH\t\tWidth of Wayland surface\n"
 		"  --height=HEIGHT\tHeight of Wayland surface\n"
 		"  --scale=SCALE\tScale factor of ouput\n"
+		"  --fullscreen\t\tRun in fullscreen mode\n"
 		"  --use-pixman\t\tUse the pixman (CPU) renderer\n"
 		"  --output-count=COUNT\tCreate multiple outputs\n"
 		"  --display=DISPLAY\tWayland display to connect to\n\n");