Migrate core from threads to async awesomeness (#3248)

* Add event loop to the core

* Add block_till_done to HA core object

* Fix some tests

* Linting core

* Fix statemachine tests

* Core test fixes

* fix block_till_done to wait for loop and queue to empty

* fix test_core for passing, and correct start/stop/block_till_done

* Fix remote tests

* Fix tests: block_till_done

* Fix linting

* Fix more tests

* Fix final linting

* Fix remote test

* remove unnecessary import

* reduce sleep to avoid slowing down the tests excessively

* fix remaining tests to wait for non-threadsafe operations

* Add async_ doc strings for event loop / coroutine info

* Fix command line test to block for the right timeout

* Fix py3.4.2 loop var access

* Fix SERVICE_CALL_LIMIT being in effect for other tests

* Fix lint errors

* Fix lint error with proper placement

* Fix slave start to not start a timer

* Add asyncio compatible listeners.

* Increase min Python version to 3.4.2

* Move async backports to util

* Add backported async tests

* Fix linting

* Simplify Python version check

* Fix lint

* Remove unneeded try/except and queue listener appproriately.

* Fix tuple vs. list unorderable error on version compare.

* Fix version tests

tests/components/test_shell_command.py

@@ -34,6 +34,7 @@ class TestShellCommand(unittest.TestCase):
 
             self.hass.services.call('shell_command', 'test_service',
                                     blocking=True)
+            self.hass.block_till_done()
 
             self.assertTrue(os.path.isfile(path))