Removed disabling rigidbodies, as that caused problems

It used to be that you couldn't have rigidbodies and
character controllers running actively on the same
object. That seems to have been changed.
Pretty Test scene update!

* Disabled the begin menu for now. It's annoying, and I find that
it's easy to forget you can disable it. It will be re-enabled for builds
* Added a collider to the plane. It no longer clips the world
* Re-scaled the plane. We'll see if these dimensions are better.
* Ground controllers work, however they are a bit rough around
the edges