changed to use instances instead of object litterals
changed to use instances instead of object litterals

griever989/PhysicsJS,VANITAX/PhysicsJS,pietro909/PhysicsJS,mcanthony/PhysicsJS,131/PhysicsJS,VANITAX/PhysicsJS,wellcaffeinated/PhysicsJS,eric-seekas/PhysicsJS,Rawneed/PhysicsJS,wellcaffeinated/PhysicsJS,Nayar/PhysicsJS,Rawneed/PhysicsJS,Luwdo/PhysicsJS,haithemaraissia/PhysicsJS,aldeed/PhysicsJS,rohit765/PhysicsJS,jpellerin/PhysicsJS,griever989/PhysicsJS,jpellerin/PhysicsJS,aldeed/PhysicsJS,pietro909/PhysicsJS,Nayar/PhysicsJS,Luwdo/PhysicsJS,eric-seekas/PhysicsJS,mcanthony/PhysicsJS,rohit765/PhysicsJS,haithemaraissia/PhysicsJS