updated uml also with qty and time

@elf-pavlik are you OK with putting this up into master? I think the only thing in this that isn't decided yet is vf:quantifiedAs. And there are quite a few other small updates and fixes.

But, even if you don't want to merge, could you take a look at how I translated the qudt and time stuff? Thought it would be good to detail that in UML land. I smushed the time stuff a bit compared to the real model. And just used one time field, which can use whatever else we choose to add. Doesn't affect the rdf implementations, which would have access to the "real" quantity and time ontologies.