v1.1.0

No changes were made, except adding Spark 2.4.0 and Scala 2.12 support.
2.12 artifacts were published too:

• spark-2.4.0-bin-hadoop2.7-scala-2.12.tgz
• mist-1.1.0-scala-2.12.tar.gz
• docker image: hydrosphere/mist:1.1.0-2.4.0-scala-2.12