Punctuation sorting bugfix

These commits address the issue described by Tod on the vufind-tech list:

  http://sourceforge.net/mailarchive/message.php?msg_id=31541882

It's a small patch to the way strings are preprocessed before being passed to ICU4j.

Since this bug demonstrated a gap in the test coverage, I've taken the opportunity to port the old Clojure-based tests over to JUnit4, and added a new Ant task to run the tests (described in the README).  I've added a test to catch this bug too.

I wasn't sure whether I should also apply this bug fix to the Solr3.1 branch?  I'm happy to do that too once it's merged into master.