Tried to implement CoreData, but does’t work yet.
Settings.m:
	-saveCoreData: should write values for brightness, unit and scale settings to the database.
	-retreiveCoreData: should read values for brightness, unit and scale settings from the database.

DDCMainViewController.h:
	-NSString *unit is not needed anymore due to changes in DDCMainViewController.m

DDCMainViewController.m:
	-didSelectNewScale: called by the DDCFlipsideViewController, sends scale to Arduino
	-didSelectUnit: called by the DDCFlipsideViewController, sends unit to Arduino
	-didUpdateBrightnessValue: called by the DDCFlipsideViewController, sends brightness-value to Arduino

DDCFlipsideViewController.m:
	-changed some Logs
	-delegate is now only notified over changed brightness value on “done”-button click.