Removed MongoDB dependency by adding Flapdoodle embedded MongoDB. That allows us to get rid of the utility module we had in place for the MongoDB samples guarding the tests to only run when a MongoDB instance is running.
Tweaked Travis setup to not require the MongoDB service anymore.
Removed the additional GeoJsonModule and only register the mixin for GeoJsonPoint to be able to read the data from the source JSON file. Removed custom logging.
A bit of polish in the README, JavaDoc.
