Use premis hasOriginalName (and hasSize) predicates on fedora:binary
resources

Expose the premis:hasOriginalName propertyfrom the HTTP API using
the Content-Disposition ("filename") header for both fcr:content
and a POST with a binary payload.

Expose originalFileName throughout the kernel's Datastream API.

Use Content-Disposition headers when retrieving content to hint
the original file name, creation and modification times.

Fixes https://www.pivotaltracker.com/story/show/61500736
Merge pull request #179 from futures/content-disposition

Use premis hasOriginalName (and hasSize) predicates on fedora:binary resources

Resolves: https://www.pivotaltracker.com/story/show/61500736