Closes #121 - Combined properties classes into FluoConfiguration

Pull request for #121

Fluo Configuration extends Apache Commons Configuration. Created unit test and updated
implementation to use new configuration class.  Added methods to verify
if configuration is set properly for client, admin, worker & oracle.
Commons does have environment interpolation.  However, it is only done when getString() is called.  For some reason, getProperty() which returns an object does not do this.  However, the getAccumuloClasspath() method uses getString()