Expose type_tag factory for type_info.
Support full bitmap index operations.

With the introduction of schema queries, VAST had restricted support for
the predicate node types: they had to be equal. But the bitmap indexes already
support more advanced queries, such as substring and IP prefix search. We now
support the full enchilada. For example, "show me all traffic not originating
from the router but in my home subnet":

    orig_h != 192.168.0.1 && orig_h in 192.168.0.0/24

Or "show me all connections that involved server data":

    history ni "d"