Add lv2:Parameter to domain of units:unit.
Remove units:name in favour of rdfs:label.
Make units.ttl a valid OWL 2 DL ontology.
Define used but undefined resources (units:name, units:render, units:symbol, units:Conversion, units:conversion, units:prefixConversion, units:to, and units:factor).
Convert documentation to HTML and use lv2:documentation.