Add tooltips to artist and maze move / jump blocks. Add arrow images to maze move blocks.

![image](https://cloud.githubusercontent.com/assets/206973/2907141/e96fc094-d618-11e3-9de8-c356b9d672f4.png)

![image](https://cloud.githubusercontent.com/assets/206973/2907292/98debb92-d61a-11e3-9862-c70f7e36ae17.png)

![image](https://cloud.githubusercontent.com/assets/206973/2907303/a7ba7fac-d61a-11e3-80f6-e9a38fce32c5.png)