#101

Changes are from branch `master` of
https://github.com/mp4096/python-control.git

There was merge conflict in how a for-loop was refactored into
`map` (here) vs. list comprehension (from PR #110).

I compared the two alternatives using %timeit of Jupyter for matrices
that would correspond to LTI systems with 10 state dimensions, 2
inputs, 2 outputs (so, the A matrix has shape (10, 10), B matrix has
shape (10,2), etc.), and with 100 state dimensions, 20 inputs,
20 outputs, all using matrices from numpy.random.random((r,c)).

The difference in timing performance does not appear
significant. However, the case of `map` was slightly faster
(approximately 500 to 900 ns less in duration), so I decided to use
that one to resolve the merge conflict.