* [Python] Improve model equality implementation
The model equality implementation template blindly tried accessing the
`__dict__` attribute of the variable to compare equality against. This
attribute does not exist for a lot of Python built-in types (`None`,
`str` etc.) and the equality check would simply crash.
This adds a simple guard to only continue with equality check if the
variable to compare is an instance of the model being compared against.
* Remove wrong auto-update of Python requirements
* python: Let logging format messages on demand
* python: Use six more
* python: Remove unused imports
* python: flake8 fixes
* python: Make examples compatible with Python 3
* python: Spelling fixes
