Fix #1139: PythonTuple.GetHashCode with None

PythonTuple.GetHashCode() takes a different code path than hash(), and
that code path did not take null into account. Use
NoneTypeOps.NoneHashCode (same as the hash() path) so that they are
consistent.
cleanup - removed Tools/IronStudio
disasble signing - hack to suppress loading assemblies from GAC
tested under CLR2
adjusted test_version to cope with a/b/RC