Only rebuild needed modules between different scala/spark version builds (#3286)
Only rebuild needed modules between different scala/spark version builds (#3286)

* Only rebuild needed modules between different scala/spark version builds

Reduces build time of `./buildmultiplescalaversions.sh clean install -DskipTests=true -Dmaven.javadocskip=true`
 from 293s to 199s
Fixes #2873

* remove obsolete spark property

kinbod/deeplearning4j,huitseeker/deeplearning4j,kinbod/deeplearning4j,kinbod/deeplearning4j,huitseeker/deeplearning4j,huitseeker/deeplearning4j,huitseeker/deeplearning4j,kinbod/deeplearning4j,huitseeker/deeplearning4j,huitseeker/deeplearning4j,kinbod/deeplearning4j,huitseeker/deeplearning4j,kinbod/deeplearning4j