Add dropdown versions of maze repeat blocks

![image](https://cloud.githubusercontent.com/assets/206973/3803291/db167466-1c18-11e4-90ca-916af63e51a7.png)

![image](https://cloud.githubusercontent.com/assets/206973/3803293/de5f269a-1c18-11e4-879c-feda47d45f31.png)