fix fairly uncontroversial stuff in my.core like
- line spacing, which isn't too annoying (e.g. unlike many inline whitespace checks that break vertical formatting)
- unused imports/variables
- too broad except
- use portable separators
- paths should be prepended with r' (so backwards slash isn't treated as escaping)
- sqlite connections should be closed (otherwise windows fails to remove the underlying db file)
- workaround for emojis via PYTHONUTF8=1 test for now
- make ZipPath portable
- properly use tox python environment everywhere
this was causing issues on Windows
e.g.
WARNING: test command found but not installed in testenv
cmd: C:\hostedtoolcache\windows\Python\3.9.12\x64\python3.EXE
* core: add ZipPath encapsulating compressed zip files
this way you don't have to unpack it first and can work as if it's a 'virtual' directory
related: https://github.com/karlicoss/HPI/issues/20
