Moving Pictures

- start.cmp now rotates a yellow cube
- It uses timer.cmp to fire off a message on an interval to spark the
  rotation
- This is the first time a script is actually doing something visible
  and interesting, so I consider this a major milestone
- Previous checkin that auto-generates system_api_meta.cpp has made
  adding new apis super convenient.
- A couple new apis, like radians and degrees are now available