GEOMESA-65 IngestFeatureCommand does not properly close FeatureWriter leading to truncated ingest

Added a CloseableFeatureWriter closure which is threaded through
the computation using Scalding's `using` facility.
Merge branch 'ltmaster' into ccrimaster

Conflicts:
	geomesa-shell/src/main/scala/geomesa/core/util/shell/IngestFeatureCommand.scala