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
Actually, I will take out the AttributeIndexFilteringIterator iterator since its not relevant to the test :) We just happen to use it when doing things.

The high level tests are all those that use the attribute index...but they aren't specific to the batch multi scanner if that makes sense. These tests are only meant to test the BMS functionality but the BMS could be used by any client side code that needs to communicate between multiple scanners.