Xi: process raw touch events

No-one can generated them yet, but if they could, we'd be processing them
like there was no tomorrow.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Chase Douglas <chase.douglas@canonical.com>

include/eventstr.h

@@ -67,6 +67,9 @@ enum EventType {
     ET_RawButtonPress,
     ET_RawButtonRelease,
     ET_RawMotion,
+    ET_RawTouchBegin,
+    ET_RawTouchUpdate,
+    ET_RawTouchEnd,
     ET_XQuartz,
     ET_Internal = 0xFF /* First byte */
 };