[WIP] K1 artist block changes

1. Refactor Turtle `switch` statement into methods
2. Add absolute direction arrow movement blocks with placeholder icons
  * ![image](https://cloud.githubusercontent.com/assets/206973/2674467/358d22c2-c102-11e3-82a0-bfc23357f74b.png)
3. Add K1 Artist sample level
  * ![image](https://cloud.githubusercontent.com/assets/206973/2674574/df77d9ca-c103-11e3-9dfc-cadcc64007df.png)