Nobody reads these notes but this update has big changes so if you find them lucky you!

- removed the physics based demo scene. CC2D doesn't really gain anything using physics for movement anymore now that the Unity 2D bugs are all patched up
- the trigger helper is gone forever. adios.
- there is a new triggerMask field for picking the layers that should fire trigger events
- Collider2D.bounds is now used for the raycast origins