[SKOS] Requirement status

Hello,

After today's teleconf, I found two minutes to check the current status of the requirements from the SKOS UCR doc [1]
I've done changes on 2 requirements that are now (partially) met, I think:
- compatibility with ISO 2788
- compatibility with OWL-DL

Best,

Antoine

[1] http://www.w3.org/2006/07/SWD/wiki/UCRMaterial/RequirementStatus