Added reference to Norconex Committer IDOL.
AbstractFileQueueCommitter and its subclasses now periodically delete 
empty directories under their queue directory. This can greatly reduce 
the directory scanning time when dealing with thousands/millions of
files, improving performance.
New MultipleCommitters class to allow defining multiple committers.
New configuration options for AbstractBatchCommitter and subclasses:
Max number of retries between commit failures, and how long to wait
between two attempts.
Fix FileNotFound issue with MultiCommitter.
Javadoc update.
Supressed deprecation warnings.
Site redesign.
New NilCommitter class.
Fixed some javadoc links.
Javadoc overview now in default location.