[CVS ci] clone, dod stack reporting

[Leopold Toetsch]

I did check in the clone changes.
- the clone vtable method get's now a dest ptr of an already created PMC
- so the newly created PMC is already anchored, which makes it possible to change clone() code, so that no unanchored objects hang around, which still is a TODO for more complex objects
- docs adjusted

Further remark: the scratchpad clone code looks dubious, the 2 lists in the data (lex) entry should probably cloned too - and at least the lex ptrs themselves.
The destroy method leaks, because we can't cleanup duplicated lex ptrs.

Can somone better knowing scratchpads comment on this please.

Also in, as discussed with Steve, is the possiblity of reporting unanchored (or bogus) objects after marking all PMC/Buffers.

leo