Change math.py to numpydoc style

[KybernetikJo]

This PR refactors the Slycot/slycot/math.py in order to be closer to the numpdoc style as discussed in #100.
Should be part of #204.

(finished 7 of 7 routines)

Routine name	Finished	Status description
mb03rd		*3
mb03vd		*3
mb03vy		*3
mb03wd		*3
mb05md		*3
mb05nd		*3
mc01td		*3

Status description:

1. numpydoc docstring sections, fixed
2. parameters data types, fixed and 1 fixed
3. optional and default values, fixed and 2 fixed

[KybernetikJo]

I have refactored the pytests of math.py. Now every wrapper has its own pytest file and a Test_class (even though there are not always multiple tests).

Now that I think about it, though, I'm not at all sure that organizing the tests in this way is the best approach. Anyway, I think I'll stick with it for now.

---

Questions:

Do we need the file "tests/CMakeLists.txt" ? Is it for conda?

set(PYSOURCE
__init__.py
test_ab01.py
test_ab04md.py
test_ab08n.py
test_ag08bd.py
test_examples.py
test_exceptions.py
test_mb.py
test_mc.py
test_sb.py
test_analysis.py
test_transform.py
test_sg02ad.py
test_sg03ad.py
test_tb05ad.py
test_td04ad.py
test_tg01ad.py
test_tg01fd.py )
install(FILES ${PYSOURCE}
DESTINATION slycot/tests)

[bnavigator]

Please rebase (and optionally squash)

[KybernetikJo]

@bnavigator I had some troubles with git, because a "git reset HEAD" I did at some point.

I think it should be OK, though.

[bnavigator]

Thanks @KybernetikJo!

For the record, contrary to the initial description of this PR, the test files have not been reorganized, following a discussion in #206.