Replaces MongoDB connection setups and teardowns in hydra-mongodb with ExternalResources
Moves data directory for elasticsearch integration test to tmp
Hides exposed testing method, cleans up ExternalResource use and removes one 'unchecked' warning.
Merge pull request #218 from laserval/mongodb-junit-external-resources

Refactoring of tests using jUnit external resources (@Rule annotation)
Removes required from SolrOutputStage parameters. Fixes #220
Merge pull request #221 from jwestberg/solr-required

Removes required from SolrOutputStage parameters. Fixes #220
Fixed typo "stdin" -> "stdout" in log messages