[WG-UMA] Draft of permission registration extension spec

This is sort of an “editor’s draft”. Thanks to Roland et al. for early feedback! Does the group want to consider this ready enough for discussion as a group work product? In which case I can put it in GitHub etc… Eve Eve Maler | cell +1 425.345.6756 | Skype: xmlgrrl | Twitter: @xmlgrrl | Calendar: xmlgrrl@gmail.com