Explicitly set android:allowBackup to true.

Signed-off-by: Jason Lynch <jason@calindora.com>
Specify US locale for dates used in log filenames.

Signed-off-by: Jason Lynch <jason@calindora.com>
Add the interface for the tracking service.

This implements all of the button logic for starting and stopping the tracking
code in the background. However, it doesn't actually do anything yet.

Signed-off-by: Jason Lynch <jason@calindora.com>