Change in repository location of 'staged' PROV-XML schemas

Hi Ivan,

There was apparently confusion about where to stage the PROV-XML schemas so they will be correctly published to /ns and not to /TR.

They were in xml/releases/NOTE-prov-xml-20130430/schemas, but to reduce confusion and prevent the inadvertent publication of the schemas to TR/ I have moved the schemas to namespace/ in the repository.

The intent is for all 4 schemas to be hosted under /ns during final publication.

The schema directory in the NOTE-prov-xml-20130430 staging directory has been removed.

Let me know if you have any questions.

Thanks
--Stephan