Makes sure all values are handled as arrays
Merge pull request #612 from projecthydra/solr_digital_object

Fix to make sure all values are handled as arrays
Adding optional yml paramters as comments so people know they exist
Merge pull request #618 from psu-stewardship/yml_options

Adding optional yml paramters as comments so people know they exist
rename ActiveFedora::Rdf to ActiveFedora::RDF
add RDF::Vocabulary subclasses for Fcrepo and ProjectHydra