Added a constant color shader that isn't affected by light
Added simple generic textures that could be used for a variety of purposes
SpawnOnceDelayed now has the option to choose if the spawner should self-destruct or not.
Added DestroyAfterTime, which simply destroys the attached object after a certain period of time in seconds
Added DestroyOnInvisible, which destroys the attached object if it goes outside of the camera's view
Updated example scene to test constant shader and new object scripts