Updated MODS User Guidelines

LC has made available a revision of the MODS user guidelines to include the new elements in version 3.2.

The major changes are:

1. Addition of 3 attributes to location url (note, access, usage)
2. Addition of 2 enumerated values to physicalDescription digitalOrigin
   (digitized microfile, digitized other analog)
3. Addition of 3 attributes under part (ID, type, order)
4. Addition of subelement genre under subject

MODS