[SPARK-4860][pyspark][sql] using Scala implementations of `sample()` and `takeSample()`
[SPARK-4860][pyspark][sql] adding sample() to JavaSchemaRDD
[SPARK-4860][pyspark][sql] using sample() method from JavaSchemaRDD
[SPARK-4860][pyspark][sql] fixing typo: from RDD to SchemaRDD
[SPARK-4860][pyspark][sql] fixing sloppy indentation for takeSampleToPython() arguments
Merge branch 'master' of https://github.com/jbencook/spark