K1 turtle: add dots every 50px

- Change dropdown images to include dots

![image](https://cloud.githubusercontent.com/assets/206973/3771638/1fff3d1c-18f7-11e4-85de-35e92edb921d.png)

![image](https://cloud.githubusercontent.com/assets/206973/3771772/69800308-18f8-11e4-8e18-67084651af25.png)

using enoughForFullSegment might be clearer