** CLASS-PROTOTYPE

[ fixed the (CLASS-PROTOTYPE (FIND-CLASS 'NULL)) issue; more general
  fix for other built-in-classes can be done in mainline post-merge ]

** DOCUMENTATION/DESCRIBE-OBJECT

Can be done post-merge, but some of these methods talk about
SB-KERNEL:CLASSOIDs rather than CL:CLASSes.  Should be fixed to refer
to user-relevant data, probably.