Silent Sms Detection (Class 0), Database Restore, Progress Bar

Sms Receiver will monitor for Class 0 messages and provide an alert when received,
details are tracked to a database table and displayed in a notification fragment.

Restore database tables using exported CSV files this will also be added into the
Db Adapter shortly to allow data to persist across database updates. Database retore added to the RequestTask class so it can be executed in the background.

Progress bar added to provide more feedback about background operations.
Service Persistence Preference & Minor cleanup

Corrected the behaviour of the Persistent Service preference and the application will
now correctly shutdown the server when destroyed if this preference is disabled.

Other minor changes.
Gradle update
Silent Sms updates and cleanup

Removed code from methods that handle the silent sms broadcast and fragment to
simplify the code associated with this operation.

Request task upgraded to use different method for the download of remote files and
processing all handled in the background.
Location & OpenCelID tweaks

Slight tweak to the processing of OpenCellID data and to logic for checks done for
cached locations.
Silent Sms Alarm Activated

Interception of Silent Sms will invoke an alarm in the persistent notification.
Silent Sms Tweaks

Removed the fragment that would display Silent Sms details as it was a basic
version of the Db Viewer.

Broadcast Receiver in the main service will now notify the user by a system alert
and also posting the alert through the notification.
OpenCellID Request, Database Backup & Restore

OpenCellID HTTP request rewritten and added to the RequestTask class so it runs in the background.

Also added the database backup and restore functions to RequestTask.
Minor updates

Minor tweaks to a number of items including moving some packages to local, declaring
some variables as final etc.