python 3.13 support. fileutils fixes and enhancements.

max_depth for iter_find_files, enter parameter for research, fixed Se…

…ntinel copy behavior, tentative 3.13 support

drop Python <3.7 support, update readthedocs

small release with sdist packaging tweaks

bugfixes for LRU, OMD, and copy_function. fill/end for windowed/pairw…

…ise.

mostly bugfixes and py310/py311 support

A few bugfixes for py3.9. minor enhancements, as well as docs and CI …

…fixes.

custom repr in format_invocation, faster iterutils import

couple of important IndexedSet fixes, iterutils.strip tools, strip_an…

…si improvements, and more

various small and medium fixes and enhancements for funcutils, setuti…

…ls, socketutils, and strutils