added driver for magnetometer mag3110
added sensor interface for mag3110 driver
added example for magnetometer sensor
Merge pull request #11 from yschroeder/pull-req/mag3110-driver

Added support for magnetometer MAG3110 on INGA 1.6
Merge branch 'develop' into yannic/inphase

Conflicts:
	platform/inga/contiki-inga-main.c