[Lg] added class for logging

  * This is part of issue #102.
[MainActivity] renamed Debug Mode

  * This is part of issue #102.
[MainActivity] now is able to turn on and off a debug mode with more logging

  * This is part of issue #102.
[Lg] now stores debug mode in settings

  * This is part of issue #102.
[Version] improved debug tag handling

  * This is part of issue #102.
[PreferencesHelper] debug mode defaults to true if Version has a debug tag

  * This is part of issue #102.
[Lg] now has Anonymizer

  * This is part of issue #102.
[GcmBroadcastReceiver] now uses logging class Lg

  * This is part of issue #102.
[MainActivity] now uses logging class Lg

  * This is part of issue #102.
[Version] now uses logging class Lg

  * This is part of issue #102.
[ContactsListFragment] now uses logging class Lg

  * This is part of issue #102.