[python-control-developers] [python-control/python-control] c99f72: Updated examples to be PEP compliant (#307)

[Bill T. <no...@gi...>]

  Branch: refs/heads/master
  Home:   https://github.com/python-control/python-control
  Commit: c99f72f51b3d82b933cdfc39e1fe0735516e820c
      https://github.com/python-control/python-control/commit/c99f72f51b3d82b933cdfc39e1fe0735516e820c
  Author: Bill Tubbs <bil...@me...>
  Date:   2019-06-08 (Sat, 08 Jun 2019)

  Changed paths:
    M examples/bdalg-matlab.py
    M examples/bode-and-nyquist-plots.ipynb
    M examples/check-controllability-and-observability.py
    M examples/genswitch.py
    M examples/phaseplots.py
    M examples/pvtol-lqr-nested.ipynb
    M examples/pvtol-lqr.py
    M examples/pvtol-nested-ss.py
    M examples/pvtol-nested.py
    M examples/robust_mimo.py
    M examples/robust_siso.py
    M examples/rss-balred.py
    M examples/secord-matlab.py
    M examples/slycot-import-test.py
    M examples/test-response.py
    M examples/tfvis.py
    M examples/type2_type3.py

  Log Message:
  -----------
  Updated examples to be PEP compliant (#307)

Multiple changes to make examples/ more PEP8 compliant:

* Updated for Python 3

* Edited to comply with Python PEPs

* Removed MATLAB-like formatting such as semi-colons, syntax and indenting PEP compliant (using PyCharm), changed imports from `from ___ import *` to things like `import matplotlib.pyplot as plt` and `import numpy as np`, removed tabs

* Removed spacing around `*` and `/` operators for consistency and as per PEP 8.

* Refactored name 'ord' which conflicts with built-in.

* Reformatted comments

* Removed tab characters

* Replaced np.matrix with np.array objects