Add support for Multi-Homed Items (aka Foreign Bibs, aka Linked Items)

Add support for Multi-Homed Items (aka Foreign Bibs, aka Linked Items)

Evergreen needs to support the ability to attach a barcoded item to more than one bibliographic record.  Use cases include:
  1. Barcoded E-Readers with preloaded content
    * Readers would all be items attached to a single "master" bib record in the traditional way, through call numbers that define their ownership
    * Each reader, as a barcoded item, can be attached through Multi-homed Items to records describing the list of preloaded content
    * These attached Multi-homed Items can be added and removed as content is swapped out on each reader
  2. Dual-language items
    * Cataloger decides which of several alternate languages is the primary, and attaches the barcoded item to that record in the traditional way
    * Alternate language records are attached to this item through Multi-homed Items
  3. "Back-to-back" books -- two books printed upside down relative to one another, with two "front" covers
    * Cataloger decides which of the two titles is the primary, and attaches the barcoded item to that record in the traditional way
    * Alternate title record is attached to this item through Multi-homed Items
  4. Bound Volumes -- Sets of individual works collected into a single barcoded package
    * Cataloger decides which of the titles is the primary (or creates a record for the collection as a whole), and attaches the barcoded item to that record in the traditional way
    * Remaining title records for the collected peices are attached to this item through Multi-homed Items

Functionality funded by Natural Resources Canada -- http://www.nrcan-rncan.gc.ca/com/

Please see http://git.esilibrary.com/?p=evergreen-equinox.git;a=shortlog;h=refs/heads/multi_home for the full commit history.

git-svn-id: svn://svn.open-ils.org/ILS/trunk@20056 dcc99617-32d9-48b4-a31d-7c20da2025e4