Implemented Android fallback for GPS via LocationManager and installed it at sensor thread, addresses XPERIA compatibility and closes #36
Added GPS delay, used in Android fallback version, to be used in Google Play Services solution.
Implemented Telephone State Sensor refered to as GSM, tested working on an API 7 device with GSM connection
Use of Neighboring Cell Info instead of API17 Cell Info
Added assertions instead of explicit checks.
Fixed FilePersistor. 

If logFile ist not writeable, the object goes to disabled mode.
Made Sensor Queue not static.
Added user prompt to enable GPS sensor if not available,
Fixed Location timestamp error. \n Using event.getTime() was off by several hours in experiment.
Merge branch 'feature/newNetworkSensors' into dev