no code changes

Do not set annex.version whenever any command is run. Just do it in init.
This ensures that, if a repo has annex.version=3, it has a git-annex
branch, so we don't have to run a command every time to check for the
branch.

Remove the old ad-hoc logic for v0 and v1, to simplify version checking.

No longer auto-upgrade to repository format 2, to avoid accidental upgrades, etc. Use git-annex upgrade when you're ready to run this version.

detect v1 repos that don't have a version set

pulled in old versions of functions for working with keys

Wrote a parser from old key filenames to new keys.

long comments :)

It compiles. It sorta works. Several subcommands are FIXME marked and
broken, because things that used to accept separate --backend and --key
params need to be changed to accept just a --key that encodes all the key
info, now that there is metadata in keys.

So, I have a type checked safe handling of filenames starting with dashes,
throughout the code.

Rename Locations functions for better consitency, and make their values
more consistent too.

Used </> rather than manually building paths. There are still more places
that manually do so, but are tricky, due to the behavior of </> when
the second FilePath is absolute. So I only changed places where
it obviously was relative.

Most of it was to do with managing annexed Content, so put there