Implemented DeviceClass Controller
Implemented DeviceClassController.
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/main/java/com/devicehive/controller/DeviceClassController.java
	src/main/java/com/devicehive/controller/DeviceController.java
	src/main/java/com/devicehive/controller/EquipmentController.java
	src/main/java/com/devicehive/controller/UserController.java
	src/main/java/com/devicehive/controller/auth/HiveSecurityContext.java