Release Notes: 0.5.9

What's new since 0.5.8?

Updated git to 2.37.1 for the helper.
Various python 3 fixes.
Fixed stream bundle
Added python and py.exe as executables tried on top of python3 and python2.
Improved handling of ill-formed local urls.
Fixed using old mercurial libraries that don't support bundlev2 with a server that does.
When fsck reports the metadata as broken, prevent further updates to the repo.
When issue #207 is detected, mark the metadata as broken
Added support for logging redirection to a file
Now ignore refs/cinnabar/replace/ refs, and always use the corresponding metadata instead.
Various git cinnabar fsck fixes.