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
Yeah, true. The tight loop just seems like a bad idea... if you're going to update it later anyway, adding 5ms is probably the easiest fix for now.