Integrate authority browse and creation support into the MARC editor

Integrate authority browse and creation support into the MARC editor

This commit changes the contextual authority menu to be based on
the authority browse interface; this should result in better
matching behavior. The browse axis (author, subject, title, topic)
is based on the context tag.

The browse interface has enabled the contextual menu to grow
"Next page" / "Previous page" menu items to enable cataloguers
to wade through long lists of similar authority entries.

The browse interface has also grown a "Create new authority record"
menu with two submenu items.

  * "Create immediately" takes the field in context and creates a new authority
     record based on that field, with matching indicators and subfields.
  * "Create and edit..." displays the MARCXML for the authority record in
     a MARC editor window before saving the record to the database.

TODO: Make the "Create..." contextual options add the $0 linking subfield
to the newly controlled field.

TODO: Address some of the flaky UI behaviour, such as having to right-click
three times on an authority-controllable field to display the authority menu.

git-svn-id: svn://svn.open-ils.org/ILS/trunk@17644 dcc99617-32d9-48b4-a31d-7c20da2025e4