version bump for release 3.2.1

merged beta and betaInternal build types.

more bug fixes and version bump.

guided altitude display bug fix.

Merge pull request DroidPlanner#1583 from DroidPlanner/feature_ekf_view

Feature ekf view

increased padding for ui elements on the flight data screen to avoid …

…clipping with the map floating action buttons.

added betaInternal build type.

action bar ui cleanup.

Tag for the 3.1.6 release.

Version 3.1.5 changelog:

* Improved rover support.
* Bug fixes.