Fix auto transition when changing room without exit_scene event (#462)

Added a new fourth button in room14 to demonstrate this.
Renamed BYPASS_LAST_SCENE to FORCE_LAST_SCENE_NULL to make it a bit clearer.
Made events "finished" and "interrupted" signals connections as ONESHOT (so they are disconnected once the signal was received).

Also removed some unused files, many others remain.
And fixed some bugs here and there.

game/rooms/room14/esc/room14.esc

@@ -14,8 +14,8 @@
 	stop
 
 # If we're coming from the same room as this one, we manage the player's position 
-# AND the transition IN manually
-> [eq ESC_LAST_SCENE room14]
+# AND the transition IN manually if we pushed that button
+> [eq ESC_LAST_SCENE room14, transition_manual]
 	teleport player start
 	
 	# Set player look left
@@ -25,6 +25,15 @@
 	transition fade_black in
 	stop
 
+# If we're coming from the same room as this one, we manage the player's position only
+> [eq ESC_LAST_SCENE room14, !transition_manual]
+	teleport player start
+	
+	# Set player look left
+	set_angle player 270
+	
+	stop
+
 
 :ready
 	queue_event worker moveworker