UI update and bug fixes

This PR updates the ui to take advantages of Android KitKat's new ui features.
Where necessary, it also fixes remaining ui layout bugs.
It also introduces a 'go to drone location' map button. 
Long pressing on either the 'go to drone' or the 'go to user' location buttons will now activate auto pan on the drone or the user.

![test](https://cloud.githubusercontent.com/assets/914968/3497939/5d9f6436-05f0-11e4-9dca-3d646824ed67.png)