REMOVE GEN_KEY. The gen_key function is entirely removed. Decided

REMOVE GEN_KEY.  The gen_key function is entirely removed.  Decided
this was OK now that import_key works, and we can't really see a
reason to keep it around.  We can resurect it down the line if need
be.  Also, removed "expert" subcommand, after promting import_key,
since it may be need semi-regularly.  The other "expert" commands are
now just not listed in the usage.