Offline

Change-Id: I6371df8e092905e2585dfd30ffa93cdf491e4f6f

Added support for searching bssids in an offline database. Just like @n76 Local-GSM-Backend.
I integrated it into your backend because it kinda makes sense ;)
If you want me too, I can also publish this as my own backend.
This makes it visible by the standard Android launcher. If you leave this off it will only be accessible via the settings menu in NLP (which is what my latest changes to my GSM location back end do.