GEOMESA-153 Remove class cast exception

* Avoids a class cast exception in a test.
GEOMESA-146 WPS import process for performance

* Implements a bulk WPS import process.
GEOMESA-122 Split OR filters into multiple queries

* Created a OrSplittingFilter Visitor which helps break apart a more complex Filter into pieces.
* Moved up the SelfClosingBatchScanner into core and implemented a basic CloseableIterator trait.