Added reference to EventLoop plugin to Motion
Changed Sets of ongoing motions and spins to contain entities in order to avoid worl collection lookups in every update cycle
Removed the start of new thread for every ongoing motion. Attribute updates now check whether motions or spins started or ended and only add Entities to or remove them from the respective list based on the new attribute values
Changed update functions for motion and spin to be executed only once.
Updates for motions and spins are now executed periodically based on the tick fired event of the event loop
Merge branch 'motion_eventloop' into develop