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.
Deft comment...  Hrrmm...  I'm tempted to say that each Iterator will process at most one ECQL filter.  If that's the case, then the naming needn't be complicated.

Do we have the complete time in the index entries?  If so, we can pass one ECQL filter to the STII for it to filter completely by the 'good' space and time constraints.