Dummy global list, for recycling and decreasing the amount of del() calls.

Added a global datum that will handle the dummy objects list, so they can be recycled.

This will decrease a lot the amount of atom/movable/del() calls.


THIS NEEDS TO BE TESTED ON A SERVER WITH A DECENT AMOUNT OF PEOPLE, ALL CLICKING AT THE SAME TIME. DO NOT MERGE IF THAT DIDN'T HAPPEN.