v6.0-beta.29

* Issue **#1115** : Add missing super.startProcessing to AbstractKafkaProducerFilter.

* Improve exception handling and logging in RemoteDataSourceProvider. Now the full url is included in dashboard connection errors.

* Change Travis build to generate sha256 hashes for release zip/jars.

* Uplift the visualisations content pack to v3.2.1

* Issue **#1100** : Fix incorrect sort direction being sent to visualisations.