nsf.c

nsf.c: - fix case, where NsfDStringPrintf() failed (when print llength including \0 was 1 byte longer than print buffer) - make sure, that the list kept for the cached parameter is just built from unshared objects; otherwise Tcl append will abort
nx.tcl:
- new package "nx::volatile"
- don't define configure parameter "-volatile" per default;
use "package req nx::volatile" instead
- don't define per method "volatile" per default;
use "::nsf::method::require ::nx::Object volatile" instead
- get rid of -volatile in nx.tcl and serializer
- update/extend regression test