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
As a question, is there an putAll which could be used instead?  I'm just wondering if more work could be done while holding a given lock?