* New black removes a few leading new lines in blocks, so many
files changed in that way.
* The "pygments" has a vulnerability, but updating that and the
restructured text checking stuff did not actually matter at
all.
* Bumped needed version for development to 3.8, since black does
not do 3.7 anymore, and it's old enough.
* For Python2, in-place operations for integers got special cases, like
they are for CPython. This preserves the Nuitka speedup.
* For strings that are not used elsewhere, the string is expanded in the
old storage location, which makes things much faster for large strings.
* Currently only local variables are handled this way. More kinds of
storage, global variables, attributes, etc. are to follow.
* This fixes part of Issue#124.
