GEOMESA-192 Enabling BatchMultiScanner

* Enable BatchMultiScanner for secondary index. Allows batching of results from
  the attribute index to the record table.
* Prevents using up client memory on large secondary index queries
* Fixed corner cases in BatchMultiScanner
It looks like this test has implementation details in it for the AttributeIndexFilteringIterator.

Are there example queries which should use this Iterator?  If so, I'd love to see a test which uses some of those at a higher level.