Support the AKN 3.0 component and portion naming mechanism in URIs

[longhotsummer]

See http://docs.oasis-open.org/legaldocml/akn-nc/v1.0/csprd02/akn-nc-v1.0-csprd02.html#_Toc447637036

This would mean

• ...main/chapter/2 would be something like ...main~chapter.2
• .../schedule/3/section/3 would be ...!schedule.3~section.3 or something.