[MLLIB] SPARK-2329 Add multi-label evaluation metrics

Implementation of various multi-label classification measures, including: Hamming-loss, strict and default Accuracy, macro-averaged Precision, Recall and F1-measure based on documents and labels, micro-averaged measures: https://issues.apache.org/jira/browse/SPARK-2329

Multi-class measures are currently in the following pull request: https://github.com/apache/spark/pull/1155
The fold operation is made with RDD. I didn't find sum in the RDD interface, that's why I used fold. I will be happy to use sum instead. http://spark.apache.org/docs/latest/api/scala/index.html#org.apache.spark.rdd.RDD