[CDG5] Pure Python HFS implementation

[Elliot Nunn]

Fellow hackers,

Tonight I got my pure-Python HFS implementation to output a volume that
can be mounted by Mac OS 9 and X (10?). Not much more work remains
before it is solid enough to use in a build system.

A slightly further-out goal is to expose the metadata underlying the
Finder's spatial metaphor: XY coordinates etc.

https://github.com/elliotnunn/machfs/