Replacing some icons, cleaning up help text, etc.

- Delete all old map code

Tweaking MapType and MapCenter icons
Added Zoom Plus/Minus icons to be used for maps
Added PiP icon for the upcoming Picture-in-Picture functionality

Too complicated supporting both modes as editor becomes more complex

- Restructured a number of MissionItem properties as well

- Moved all MavManager functionality to Vehicle
- Updated all code to use Vehicle instead of MavManager
- Removed MavManager

Can now scroll to work on laptops and tablets. Plus many other changes.

Usability plus, new features:
- 3DR Radio support
- APM Stack support

Everything is now based off of default font pixel size

- More more on making QGCView real
- Converted Parameter Editor to QGCView

Initial rendering of Waypoints