Prevent collision checks against objects that may have been removed from the scene.

Previously, the call `object2._physijs.id` could be undefined.
Merge pull request #81 from cacheflowe/undefined-fix

Prevent collision checks on removed objects
memory issue

add destroy for "new ammo.btTransform",
add _vec3_1, _vec3_2, _vec3_3, _quat and delete calls for new ammo.btVector3 and new ammo.btQuaternion
Merge pull request #84 from stoomm/master

Memory issue