Sensor Data Collector

Invalid date

* New: StepCounter implemented
* New: re-implemented export menu (now preferences)
* Improvement: database export/delete
* Improvement: location detection
* Bugfix: wrong sensor selftest was performed
* Bugfix: if gyroscope sensor was recorded then the values were multiple times stored (wear)
* Bugfix: the app crashed if GPS was tried to activate (Android 6)
* Bugfix: the app crashed if a not supported sensor was available (wear)
* Bugfix: recorded data was not transferred (wear)
* minor changes