LiteJet: Unit tests and new trigger options held_more_than and held_less_than. (#4473)

* LiteJet: Unit tests and new trigger options held_more_than and held_less_than.
* Unit tests for the LiteJet component and associated platforms. Coverage is almost 100% -- just misses one line.
* The automation LiteJet trigger returns an empty "removal" function to ensure the automation base is happy with it. The pylitejet library doesn't actually support a real removal.
* The automation LiteJet trigger can detect hold time and act appropriately to support things like short tap or long hold.

* LiteJet: Fix indent in unit test source code.

* LiteJet: Fix test_include_switches_* unit tests on Python 3.5

* LiteJet: Remove wait for state existence from unit tests. Recent fixes to discovery make this no longer necessary.