added test for author-remove button on Describe Submission page

Added Selenium test for remove-author button on the Describe
Submisison page. Note that this commit adds code with runs the
risk of an infinite loop, if an encountered problem with the
.click() method persists. This commit has been tested against
Firefox and runs to completion successfully.
Merge branch 'trello-71' of github.com:rnathanday/dryad-repo into trello-71