Add possible capabilities CURSOR_PLANE and ARBITRARY_MODE

The CURSOR_PLANE capability indicates that the backend has a concept of a
cursor plane and can handle a cursor without compositing.  This is currently
only advertised by the DRM backend.

The ARBITRARY_MODE flag specifies that the backend is capable of switching to
virtually any resolution.  This is currently only advertised in the RDP
backend.  While it's a bit buggy right now, it should be capable of this.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
diff --git a/src/compositor.h b/src/compositor.h
index 37ad17f..15d6e03 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -558,6 +558,12 @@
 
 	/* screencaptures need to be y-flipped */
 	WESTON_CAP_CAPTURE_YFLIP		= 0x0002,
+
+	/* backend/renderer has a seperate cursor plane */
+	WESTON_CAP_CURSOR_PLANE			= 0x0004,
+
+	/* backend supports setting arbitrary resolutions */
+	WESTON_CAP_ARBITRARY_MODES		= 0x0008,
 };
 
 struct weston_compositor {