SET_VT:  Change to the specified virtual terminal.
This is useful for logins which don't own /dev/console
but are still console logins.  Only supported on Linux
currently, other places will just get ERROR 8.
Only supported on connections that passed AUTH_LOCAL.
Supported since: 2.5.90.0
Arguments:  <vt>
Answers:
OK
ERROR <err number> <english error description>
0 = Not implemented
8 = Virtual terminals not supported
9 = Invalid virtual terminal number
100 = Not authenticated
200 = Too many messages
999 = Unknown error
