Add Junit dependency and tests around .util Java wrapper package

[vickumar1981]

Though the .util Java package wrapper class, StringDistince, calls the same underlying implementation as the Scala version, there is a chance of missing parameters/incorrect syntax with the wrapper that could go uncaught. sbt will run on Scala sources, but can add Junit, and map to an sbt task to run both sets of tests.

• Add Junit as a dependency
• Create a task for running the java/junit tests
• Include java sources in coverage report (Is this even possible?)