removed the need for p-string routines, so they were removed. Also
removed alloc256/free256 and associated data structures.
In removing calls, found instances in pwd & prefix commands and prompt
handler where current directory name was assumed to be < 256 characters;
recoded to use a flexible buffer size.
Updated and expanded mmdebug.asm routines that perform error checking on
memory management calls. Added macros ~NEW and ~DISPOSE that invoke either
the real or debug routines.
Fixed call to read $TERM variable's length to fix PR#81.
Removed echo of data when setting value of $< in expandvars (expand.asm).
The characters are echoed as they are typed and do not need to be reprinted
on stdout after carriage-return is typed.
Added error checking to the various flavors of prefix (just like cd):
- Verify 2nd parameter is a valid directory before setting.
- Verify 1st parameter < 32 before displaying or setting.