loci: remove metadata from of_object

These fields were never used. Saves 32 bytes per of_object.
loci: remove object tracking

This feature is not used by Indigo anymore. Saves 16 bytes per of_object.
loci: move per-obj function pointers to global tables

This saves 32 bytes per of_object.
loci: inline of_wire_object into of_object

This extra layer of structs was not needed.
loci: remove owned field from of_object

This field was redundant with the parent field. Saves 8 bytes per of_object.
Merge into master from pull request #238:
shrink of_object_t (https://github.com/floodlight/loxigen/pull/238)