Added add_device_type to DeviceManager that takes a handler class (class object or string) and creates the necessary device type, command and arguments for the handler and saves it to the database
Added tests to test DeviceManager.add_device_type. Also added a SampleDevice class that tests use of the handler functions' construct pattern and command keywords
Corrected views.index to vcs.views.index in vcs.urls.py
Adding in the handler_function decorator
Disabled the db router for the time being