a valid parse tree to caller, so caller must free the tree.

Document and fix code generation for try statements.
Use two bytes for all arguments.
Avoid duplicate entries in lists of constants and names.

Added support for class definitions.
Reorganized main interpreter loop to fetch op and arg once at the head.
Use two bytes for arguments (see ceval.c).

The realloc() call would move the list head without fixing the
pointers to in the the chain of allocated objects...

Remove (broken) compatibility hacks from cutbuffer interface.

Added check for negative refcnt in DELREF.

This makes it possible to cut/paste strings wuth embedded null bytes.