Object::type_info: added unit_name property and ctor.

Object::Unit:
	replaced type property with type_info property;¹
	added get_unit_name().

Object/Ops: added unit name to identity format.

test: updated for API changes.

1: For size, since type_info already contains type, there's no reason
to store it separately. This also removes the get_type_info_impl()
function, since we want the type_info to be fixed (e.g., user-defined
unit could return a different type_info every call).
Hive, Node: added UnitBasic type_info defs in src files for linkage.
Node::UnitBasic: corrected unit name in info.
Object/Ops: switched to bare ID in identity printing.¹

1: There was no way to tell two Hives apart if you just looked
at their identities. Since the type is in the identity, we don't
need to translate to NULL_ID for the member-object perspective.