Update Apache Spark to 3.0.1 (#302)

Move to Apache Spark 3.0.0, Python 3.6 and drop Python 2.7 (#301)

* Move to Apache Spark 3.0.0, Python 3.6 and drop Python 2.7

This change updates to Apache Spark 3.0.0 and Python 3.6 for
the Python images. The "pyspark" and "pysyark-inc" images
will now use Python 3.6, there will be no py27 images or
templates.

Additionally, support for the sparklyr image has been dropped.
The previous sparklyr images for Spark 2.4 will remain.

* Set the default spark test image to openshift-spark:3.0

* Limit testing

Limit testing to the builddc templates, incomplete image builds,
and sparkonk8s. Fixup incomplete inputs for spark 3.

* Fix incomplete tests to work with clusterconfig and image mods

* Missing initial build in incomplete test for pyspark

* Simplify test_exit test

* Add clusterconfig for incomplete image java and scala tests

Update spark version to 2.4.5 (#299)

Update spark version to 2.4.4

Fix incomplete test to handle missing md5

Update oshinko-cli version to v0.5.6

Mmodify start.sh to account for output changes in yaml/json
for get

Change base image for java s2i to fabric8/s2i-java:2.2.0 from latest

 Update the oshinko CLI version to v0.5.3

Merge pull request #215 from radanalyticsio/releaseV0.5.2

releasev0.5.2

Update the oshinko CLI version to v0.5.1