Adding groups to physics engine

Hi Brent,

I think I am making things quite complex, I already have three different layers each with the their own collision filters to make sure they don’t collide… but as the minigames themselves don’t use physics I think I should be fine. I actually disable the physics engine when they’re active. 

However I think in terms of adding a group, using piotrz55’s suggestion has worked for me. There’s been a lot of additional work I’ve had to do in the supporting code to accommodate groups as objects, but simply checking for a numChildren field and adjusting the centre x and y coordinates accordingly has so far solved all the problems.

Thanks for all the help