[Finishes #79485598] Make variable-enabled blocks availible in Artist levelbuilder

![screen shot 2014-09-25 at 11 05 18 am](https://cloud.githubusercontent.com/assets/413693/4409564/913e919a-44de-11e4-8bae-09ac8737a491.png)

Updated Artist levelbuilder to show Move, Jump and Turn blocks that accept a variable instead of fixed number:

<img src="https://cloud.githubusercontent.com/assets/413693/4409576/a0508d64-44de-11e4-84d6-f801e3906882.png" width="300">