* Update unifi.py
Add support for a site that is not the default within the Unifi Controller.
i.e. A controller with multiple sites:
- Home
- Friends
- Parents (default)
Supplying the identifier for 'Home' now means that the devices tracked will be associated with 'Home'.
* Update test_unifi.py
Fix test modules as well.
Ubiquiti's Unifi WAP infrastructure has a central controller (like mfi and uvc)
that can be queried for client status. This adds a device_tracker module that
can report the state of any client connected to the controller.
