Wordsearch/spelling bee

![image](https://cloud.githubusercontent.com/assets/1767466/3317771/ef183fb2-f710-11e3-8c96-b92576099fb7.png)
Start polishing spelling bee some, using the same assets as in the Bee levels.  There's still a few things left to do, but I wanted to get this in as it's becoming a fairly large change.

Replace letter images with actual text/CSS.

Some code cleanup
- Made a mazeUtils file which only contains cellId right now (makes more sense than having it on DirtDrawer).  Still could/probably should have some of the elements in Maze use the foo_1_1 format instead of foo9
- When performing a step that has multiple actions (i.e. turn and move), schedule all the move animations to happen after all of the turn animations.  Previously this wasn't happening and got is into trouble because we had a step that consisted of move and finish and we would play the finish sound while we were still moving. 
Oi. Might be able to detect the W/H using `getBBox()` like done in this WIP: https://github.com/code-dot-org/blockly-core/pull/100/files#diff-092ff61155f6103cdfa1100af6161654R78