Refactored bricklets.py

added if before each variable to support singel variable logging
- functions which only log 1 variable only use the timer variable
 e.g. Barometer Air Pressure -> is logged with Air Pressure=1000
        GPS Coordinates          -> log interval is with Coordinates=1000
                     and variables are: Longitude=true ;or false
Changed csv header names

changed NAME to DEVICE_IDENTIFIER
changed bricklets accordingly