More Python snippets

Especially unittest.defaultTestLoader.loadTestsFromName(__name__), I
always forget how to automagically load all test cases from this file.
Make <C-L> in insert mode repeat the function signature

Mnemonic: "redraw" as in "redraw the function signature I saw just a
minute ago.

Attempts to make <C-L> in normal mode do this ended up unsatisfactory
for various reasons I neglected to write down and then promptly forgot.

Note (this was surpsising to me) that by default <C-L> in insert mode
inserts a literal ^L control character.
Longer docstrings often make syntax look wrong

Let's see if syn sync fromstart slows everything down too much or if the
cost is acceptable.
Test switcher for another of my projects

I wish I could tell it "if there are only two .py files, and one of them
is tests.py, then switch to the other one".  (There could be a third
file, setup.py, that ought to be ignored.  But of mgp2df has a fourth
.py which would break that logic anyway.)
Get a better ReStructuredText highlighter

Chosen after extensive review of available options, see
https://gist.github.com/mgedmin/4c50279b90011e239a1a

I still feel mildly guilty that I haven't published my own patched
rest.vim.
I often use $ or ^ or * or # right after leaving insert mode
All txt files in ivija are ReStructuredText files
Snippets for doctest files
flake8 snippet for setup.cfg
'barcode' is a word, right?