script: Allow warping to states

Do not just allow animating states connected to signals: add a "warp"
optional key that ends up calling clutter_state_warp_to_state(). This
is useful for debugging.

clutter/clutter-script-private.h

@@ -94,6 +94,7 @@ typedef struct {
   GConnectFlags flags;
 
   guint is_handler : 1;
+  guint warp_to    : 1;
 } SignalInfo;
 
 void property_info_free (gpointer data);