switched to using 1 thread, changed println stmts to logging calls, code cleanup

The main change in this pull request is simply to have the thrift server use only 1 thread since clear nlp currently appears to be not threadsafe.

The server now uses the slf4j-log4j12 logging library, which was already in the pom.xml, instead of making system.err.println() calls.

Also, I loaded the code in eclipse and corrected the indentation.

The previous version led to mysterious nullpointerexceptions.  I tested this by parsing 300 documents, 20 requests at a time, and this version doesn't cause any exceptions (I only spot-checked a few of the parses but didn't see anything wrong there).