The current Raspbian uses an older version of pylint
that suffers from a recursion overflow. Hacked a deeper
recursion limit to work around this issue.
Also directly calling 'pylint' does not work in Raspbian.
Instead of trying to figure out why, I just use 'python3 -m'
to invoke pylint.
Now I can run any Python unit test by name, or specify 'all'
to run them all. This way I don't have to update scripts
every time I add a new Python unit test.
I like what I did to the JavaScript tests, where I no longer
need to update scripts when I add a new unit test.
So I have decided to do the same for the other languages,
starting with Python.
I had to increase certain error tolerances in the unit tests.
Reworked the unit tests to make more sense by waiting until
each language step is done to check against each other.
That way I can run a single language step independently.
The problem was that the Python "%" operator does not behave
exactly like the C function fmod(). However, there is a Python
function math.fmod() that does act just like its counterpart in C.
Now astro_check output is *identical* between Python and C,
at least on my Windows 10 laptop.
Reinstated "ctest diff" in unit tests to make sure the
two implementations stay in sync.
