Use Python 3 instead of Python 2 if addons are executed directly.
Running cert.py and misra.py against test/cfg/std.c.dump shows that
Python 3 needs only half the time compared to Python 2. I have tested
it repeatedly and the results are always the same. This is no surprise
at all. The memory footprint is very likely also significantly better
but i have not tested it.
With multiple configurations, option --dump only dumps
the last configuration.
Fix it to dump every configuration.
Also update all Python addons so that they can handle
multiple-configuration dumps.
Additionally run autopep8 on addons/*.py.
The results of 'make test' before and after applying
this commit are identical.