Watch out for a null pointer in location provider.

Fixed #208.
Merge branch 'master' into next
Update to next development release.
Revert "Use an explicit intent to start VehicleService."

This broke permissions for all third-party apps. A big oops.

This reverts commit 346e0dff27c72855ba83000e788ecb215e08912f.
Don't register listeners in location provider unless it is active.
Watch out for an uninitialized vehicle service in a background task.

Fixed #209.
Update TODO about explicit service intent.

See #213.
Set component of VehicleService intent to make it explicit.

Fixed #213.
Fix a typo.
Remove intent filter from tests package.
Update to 5.0_r2.
Update Android dependencies for CI and don't bother with android-10.
Use a separate field for JSON timestamp to preserve fractional part.

Fixed #214
Simplify trace file timestamp playback and just use miliseconds.
Update android maven plugin to 4.0 release.
Briefly disconnect and reconnect VI when restarting trace file.

Fixed #212.
Update changelog and versions for v6.0.4 release.