Added stuff for the conceptual model.
Improved the metadata according to meetings with BLO and EJA
Added authority metadata unit and improved the descMetadata for a work.
Merge branch 'master' into conceptual_model
Added some of the relations between authority metadtata and work/instanse
Added all relations between AuthorityMetadataUnits and Entities (which should be renamed to Work). Also made method for easy extraction of all the relations.
Added better comments
Merge remote-tracking branch 'origin' into conceptual_model
Added a lot of stuff for the conceptual model. Including authority metadata unit with UI and specs.
Added an example of a MODS record which Valhal should be able to make a round-trip upon.