A first hack at crosswalked datastreams; working only for RDFDatastreams, and only if persisted to Fedora.
Added generalized crosswalkable. Works with RelsExtDatastream now as well.
Updated crosswalkable to be able to handle ActiveFedora 6.5.1.
Updated crosswalkable to be able to handle deep OMDatastream fields.
Merge pull request #6 from osulp/feature/crosswalks

Added metadata crosswalks.