V0121 (#42)

* session.timetable_extended + additional properties PeriodObject

* more info Periodobject

* Create codeql-analysis.yml

* cleanup

* new info: teacher1 and teacher2 in KlassenObject

* change backcolor/forecolor to Result or None
added PeriodObject.code_color

* Update .gitignore

added additional directories

* tox: up to Python 3.10

fixed deprecated assert_

* added "Rights needed" to documentation

* fix teacher1, teacher2

* remove double code

* version bump 0.1.20, remove python2 from supported versions

* add utf-8 to make readthedocs happy

setup.py

@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+# -*- coding: utf-8 -*-
 """
     This file is part of python-webuntis