GEOMESA-118 Implement handling for more complex geometric filter

* Pushes geometric ECQL filters into the STII/IndexIterator.
 This enables improved handling for other topological predicates along with conjunctions.
[picky] if "Preds" is short for "Predicates", please write it out.  It took me longer to guess it than I should admit, but I hope I'm not the only one that would be confused for a moment.