Trello-71: FEAT: Add/remove and reorder authors and other terms

This changeset enables updates to metadata fields in the "Describe publication" and "Add and Describe Data File" forms without a server call for each change. In particular, it enables (a) reordering metadata items, and (b) editing metadata items, without a form refresh. Mockups and feature description are available in the card: https://trello.com/c/fjojR7Wl/71-feat-add-remove-and-reorder-authors.

The Selenium test written for this code can be run in GUI mode from the subdirectory `dryad-repo/selenium` using the command:
```
mvn package -DseleniumTestURL="http://localhost:9999" -Dtest=DescribePublicationAJAXTest
```
This test requires that a local test server be running, with a test user `seleniumtest@datadryad.org` and the password indicated in the test class. The POM file in the Selenium directory was updated to enable Selenium to run with FF 34.0 on OSX (not tested otherwise).