* Use pip install --user if venv not active

* Set PYTHONUSERBASE to deps directory, when installing with --user
  option.
* Reset --prefix option to workaround incompatability when installing
  with --user option. This requires pip version 8.0.0 or greater.
* Require pip version 8.0.3.
* Do not delete deps directory on home assistant upgrade.
* Fix local lib mount and check package exist.

* Update and add tests

* Fix upgrade from before version 0.46

* Extract function to get user site

* Add function(s) to package util to get user site.
* Use async subprocess for one of the functions to get user site.
* Add function to package util to check if virtual environment is
  active.
* Add and update tests.

* Update version for last removal of deps dir

* Address comments

* Rewrite package util tests with pytest

* Rewrite all existing unittest class based tests for package util as
  test functions, and capitalize pytest fixtures.
* Add test for installing with target inside venv.