GEOMESA-106 initial work on tubeselect

didn't include gapfilling yet...suggestions esp. needed on the TubeVisitor object...should those methods move somewhere else?

geomesa-core/src/test/resources/wps-tube/json2.xml shows how to tube based on a query
geomesa-core/src/test/resources/wps-tube/json3.xml shows how to tube with user input