workflows: improve holdingpen data display

* Adds a new function to BibWorkflowObject that tries to
  return a well formatted representation of the data.

* Improves the formatting sequence when displaying data from
  workflow objects in Holding Pen to not cause exceptions when
  data is non-XML. Data is now shown as a pretty string when
  not formattable by formatter or legacy.bibfield.
Merge pull request #130 from jalavik/workflows-hp-format

workflows: improve holdingpen data display
various fixes

* Fix for login redirect not working with missing referrer;
* Moves messages JavaScript to static folder and fixes select all checkbox;
* Fixes 404 when clicking on tag in list preview;
* Adds licensing information;
* Fixes pybabel issue which prevented message sending;
* websubmit pybabel fix.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>