Markers, Mission - distance from prev waypoint in mission planner w/ live update while dragging

Builds on #324... 

Markers:
Zoom:
- Same as #324

Mission:
- right aligned distance view added to the mission planner fragment.

![screenshot_2013-10-02-08-29-10](https://f.cloud.github.com/assets/4014433/1268785/a5f461f0-2ce8-11e3-8537-6d25ae4a0e58.png)