QuotaBytes consistency of var names.

The cmd-line user-facing flags is quota=100MB, but internally, we keep
it consistent with explicit units of "QuotaBytes".
Ephermeral versus memory-only and more cmd-line usage.

Seeing if "ephemeral" level makes more sense than memory-only level as
the name of the cmd-line flag.
Sub-command: cbgb version

Example...

    $ ./cbgb version
    0.0.0