Add world_to_window

Add world_to_window() function

2.11.6

Added the parameter fixed_zoom for the sticky GO to keep a fixed zoom, regardless of the camera zoom.

2.11.5

Added a feature to add "sticky" game objects.
Useful to add a game object that acts as a GUI node, but can still interact with other gameobjects from the same collection.

Example:

msg.post("/camera#script", "add_sticky_go", {
	go=hash("/bin"), -- the game object you want to display as sticky
	camera=hash("/camera"), -- the ID of the camera
	position = vmath.vector3(1120,80,.3) -- The position on screen
})