fixes #592, adds initial FITS datastream spec tests. all tests pass.
fixes #592, adds initial FITS datastream spec tests. all tests pass.

ndlib/scholarsphere,jeremyf/sufia,zhang4952/scholarsphere,zhang4952/scholarsphere,ndlib/scholarsphere,jeremyf/sufia,samvera/hyrax,samvera/hyrax,zhang4952/scholarsphere,samvera/hyrax,ndlib/scholarsphere,samvera/hyrax,zhang4952/scholarsphere