Rewrite the mouse API

I wasn't aware of the fact that 1000, 1002 and 1003 are mutually
exclusive and turn each other off.

Also now it's not needed to set the protocol, it gets set by default.

demo-draw.c

@@ -165,7 +165,6 @@ main (int argc, char *argv[])
 		exit (EXIT_FAILURE);
 	}
 
-	termo_set_mouse_proto (tk, termo_guess_mouse_proto (tk));
 	termo_set_mouse_tracking_mode (tk, TERMO_MOUSE_TRACKING_DRAG);
 
 	// Set up curses for our drawing needs