used rightsExtension instead of rightsStatement in foxml and premis xslts.

Cleaned out the rightsStatement bits and replaced with rightsExtension
element.
Fixed issue with dc:rights element embedded in rightsExtension

yep … did that. Added xmlns for dc and oai_dc as well.
Merge pull request #20 from dmoses/7.x

used rightsExtension instead of rightsStatement in foxml and premis xslt...