to the node_types_auxtypes and node_auxtypes tables. The goal is to
not have a gaggle of fake types in the node_types table, but rather to
store the virtual types that a node (type) can take on, in the two aux
tables (node_auxtypes holds the count). This removes part of the
special handling of virtual types from ptopgen, and cuts down the
number of bogus entries in the node_types table.

I also did some cleanup. Got rid of a bunch of separate hash tables
and combined into a single hash of "records" indexed by type. This
script could use quite a bit more such cleanup.