Scenario 2

This is not ready for merge. I just want to get some eyes on it.

@kadst43 
This was one of the things I wanted you to look at. The reason to move it is because both scenarios are using the same `self` that's in secnario.js. In order to set the blockly palette and just to get that `self` variable to switch to the new scenario, I had to move those commands down to entering. I can remove that function and put it into entering, but resetting the scenario doesn't need to do all of that. I may just rename `onSceneReady` to something like `startScenario` and have that function call `enter` at the bottom instead of calling `enter` directly.