Cleaned up methods for consistency.  Most methods now populate a property of the AAGCloudSensor object instead of returning a value.

Certain methods now do the medianing of 5 values as advised by the manual.  Also certain methods now do calculations to convert from digital number to a value as described in the manual.

System now writes two telemetry files, one for SAFE/UNSAFE condition only (with timestamp), and the other with complete telemetry.
Edited is_safe() method to work with the dual telemetry file as described in the previous commit for AAGCloudSensor.py
Merge branch 'develop' of https://github.com/panoptes/POCS into develop