Prettyfied 21 state version, added python plotting tools

Hi Paul,

This paul should be non-intrunsive for your current setup, as I just have added an alternative test harness. Code wise the alternative harness (estimator.cpp and estimator.h as well as main_closed_loop_float_test.c) is a lot cleaner, but I tried hard to not break the basic logic or rename variables. It essentially has the minimum level of modifications to resolve the main shortcomings and lack of generality.

It would be great if you would be willing to adopt it as your test harness. I'd be happy to make adjustments so that you feel home on it.

-Lorenz