GEOMESA-328 Fix IndexIterator exception
 * The fix is from @anthony-ccri.
 * The tests show the exceptions which we observed on tablet servers.
GEOMESA-334, 335 Add zookeepers, instance name and Separate Export from FeaturesTools

zookeepers and instance-name can be added to any command line argument. This is useful for cases where instanceName and zookeepers
cannot automatically be found. Additionally, auths and visibilities have been added to all commands. Finally, Export has been separated
out of FeaturesTools and Tools to add more flexibility in Export.
changing hadoop_conf to hadoop_conf_dir
addressing comments