GEOMESA-494 GEOMESA-523 GEOMESA-525 Replace scopt with jcommander

* Replaced scopt with jCommander
* Refactored arguments into common classes
* logged to stderr instead of stdout to support redirecting of ouput (removed stdout flag) (GEOMESA-523)
* added "json" in addition to "geojson format"
* updated readme
* Bundled SLF4j with assembly (GEOMESA-525)
getAttribute() returns `AnyRef` so you have to call `toString` before `toDouble` which also handles the case of if the attr is a string or a double or a float