Import Shelly symbols to CL-USER package in a dumped core.
Raise an error if CIM_HOME & LISP_IMPL is not set.
Stop using 'cl' command because it's slow.
Stop check-version.
Set SBCL_HOME.
Doesn't display arglist in Help if failed to get it.
Show the help message if the action is empty.
Add 'upgrade' command.