Problem: the `set` and `clear` subcommands don't clearly convey their
intent — `set` reads like a generic setter rather than an auth action,
and `clear` overloads single-platform and all-platform semantics in one
subcommand.
Solution: rename `set` to `login`, split `clear` into `logout`
(per-platform, defaults to active) and `clear` (all platforms). Update
parser, dispatcher, tab completion, and vimdoc.
Barrett Ruth
c689b3e462
