Fix for ALWAYSUP nodes and fix for switches with interface entries.
In detail: 1. Added TBDB_NODESTATE_ALWAYSUP to libdb.pm for representing the ALWAYSUP eventstate. 2. Modified free node calculation in ptopgen to include ALWAYSUP nodes. 3. Added code to ptopgen to correctly handle the case of a NULL iface column, which happens when switches have interface (as they do in Wisconsin), but assign_wrapper expects (null) for their iface rather than "".