Remove requirement to include Guava JAR

I wanted to remove Guava as a dependency in our pom.  This makes DataFu easier to use.  We are not using very many parts of Guava.  So, I tried autojarring it, which packages Guava in DataFu and includes only what we need (followed by jarjar to rename the packages).  This ended up pulling in a lot of Guava, as we were using ImmutableList in several places, which apparently has many downstream dependencies in the JAR.  I replaced these calls in DataFu with Arrays calls.  Arrays ships with Java.  Now there is just a handful of classes we pull in from Guava.  The file size is not significantly changed as a result.  The only dependency now in our pom is joda-time.