loci: generate version names from OFVersions
loci: remove unused type maps
loci: remove dead code
loci: clean up generating remaining type_maps
loci: remove last use of inheritance_data
loci: remove inheritance_data
loci: remove dead code and old comments
loci: add a function to determine whether a class is an inheritance root
loci: store unmangled class name in inheritance_map

Instead of just the portion after the base class name.
loci: rewrite class_is_tlv16

Now inspects the members instead of hardcoding class names.
loci: rewrite class_is_u16_len

Now inspects memebrs instead of hardcoding class names.
ir: add method to return inheritance root of a class
loci: use inheritance_root from the IR

The roots no longer need to be hardcoded. 'of_header' was the only special
case.
loci: rewrite build_class_metadata

Now tlv16 and u16-len classes don't need to be hardcoded.
loci: fix testing embedded OXMs

The OXM embedded inside a set-field action needs special handling just like
bsn_vport. We have to pick which subclass to use.
loci: remove of_wire_id_valid

Validation has been done by the wire_type_get functions for a while now.
Merge into master from pull request #326:
LOCI cleanup (https://github.com/floodlight/loxigen/pull/326)