Remove sync interface, add asyncio discovery (#14)

* do not update inside __repr__

* Convert discovery to asyncio

* Use asyncio.DatagramProtocol
* Cleanup parameters, no more positional arguments

Closes #7

* Remove sync interface

* This requires #13 to be merged. Closes #12.
* Converts cli to use asyncio.run() where needed.
* The children from smartstrips is being initialized during the first update call.

* Convert on and off commands to use asyncio.run

* conftest: do the initial update automatically for the device, cleans up tests a bit

* return subdevices alias for strip plugs, remove sync from docstrings

* Make tests pass using pytest-asyncio

* Simplify tests and use pytest-asyncio.
* Removed the emeter tests for child devices, as this information do not seem to exist (based on the dummy sysinfo data). Can be added again if needed.
* Remove sync from docstrings.

* Fix incorrect type hint

* Add type hints and some docstrings to discovery

tox.ini

@@ -14,8 +14,8 @@ deps=
   pytest-cov
   voluptuous
   typing
-  deprecation
   flake8
+  pytest-asyncio
 commands=
     py.test --cov --cov-config=tox.ini kasa