title: Mahout and Spark version compatibility
body: <p>I am currently using Mahout 0.13.0. When I try to use spark-itemsimilarity I get an error:</p>
  
  <p>Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/spark/SparkConf</p>
  
  <p>I suspect it may be an issue with Spark version, but I can't find what version of Spark do I need. I am currently using Spark 2.1.0.</p>
  
  <p>So my question is, with which version of Spark is Mahout 0.13.0 compatible?</p>