GEOMESA-159 Eliminate redundant copies of a value in the SimpleFeatureFilteringIterator
GEOMESA-288 Export to stdOut

Exporting to stdOut is now achievable by giving the export command the -s or --stdout flag. Additionally, the list and describe commands now have a -q or --quiet option for better piping of their outputs.
GEOMESA-278 removing unused action page
GEOMESA-291 adding more data store params to GeoServer interface
GEOMESA-268 updating menu icons in geoserver
GEOMESA-280 fixing NPE for non-existing props