GEOMESA-215 GeoMesa query should be exclusive of temporal filter date bo...

...unds for BEGIN, AFTER

* Partitions temporal predicates out and passes them to the STII/AIFI/IndexIterator.
* Adds special handling for DWithin.  (More special cases will be produced as we move away from FilterToAccumulo.)
Thanks to Hunter Provyn for providing the unit tests in FeatureWritersTest.scala.
Just to be sure I'm reading this right:  The `Filter` provides a literal that is meant to be a measurement in meters, we convert that to degrees, and then build a new dwithin `Filter` using the measurement in degrees that we label as "meters".  Correct?