Added an RISCreator class and attempted to add a button on the index default html which will provide the RIS export

Signed-off-by: Joe Fennimore <jrf118@case.edu>
The new RIS citation writer officially matches the functionality of the last RIS citation writer.
When the Export RIS button is pressed, a text file with a .ris extension is sent to the browser and downloaded.

The ris creator is in the models directory.  An instance of the creator is created in the catalog controller,
and the method in the controller which does is called in the _index_default.html.erb

Signed-off-by: Joe Fennimore <jrf118@case.edu>
Moved the RIS button to be inside of the page for one object in the collection.  I had to modify the export_ris method in the catalog controller slightly so that it used the id passed into the method from the url. The routes.rb was also updated to reflect this change.

Signed-off-by: Joe Fennimore <jrf118@case.edu>
ris_creator_spec works and runs three different tests, though the conditions are very similar in most possible calls
to the ris_creator. I also cleaned out ris_creator, removing some methods and comments that werent being used or
giving important information.

Signed-off-by: Joe Fennimore <jrf118@case.edu>