pazi edit: allow editing the database

[euank]

I think a subcommand to manually de-weight or delete entries would be very handy.

If I could type pazi edit and be dropped into my $EDITOR with a human readable representation of the database, and at the end have pazi re-create its database based on those edits, I think that would be rad.

[euank]

Autojump has some nice utility helpers for increasing and decreasing a directory's weight (in the form of --increase and --decrease).

Those could also be handy in addition to pazi edit