Add SetDifference, HyperLogLogPlusPlus, and improve tests

This adds two new UDFs: SetDifference and HyperLogLogPlusPlus.  The latter uses the HyperLogLog++ implementation from the excellent stream-lib library.  

I've also improved how DataFu is tested and cleaned up the ivy.xml in the process.  The main issue I was concerned with was that fastutil is packaged in DataFu under a different namespace (so the massive JAR isn't required) but the fastutil JAR is used while testing.  This means we can't be sure that DataFu works without the fastutil JAR being downloaded.

I've more cleanly separated the dependencies.  The fastutil JAR is now under a "packaged" configuration, which isn't used while testing since it is assumed that the necessary classes are packaged in DataFu.

In addition I have packaged the commons-math and stream libraries in datafu under a different namespace using autojar and jarjar.  This is the same technique I used for fastutil.  I also upgraded commons-math to 2.2.

Also I fixed the eclipse .classpath, which had problems due to the versions being in a separate file now.