[SPARK-1458] [PySpark] Expose sc.version in Java and PySpark

Author: Josh Rosen <joshrosen@apache.org>

Closes #1596 from JoshRosen/spark-1458 and squashes the following commits:

fdbb0bf [Josh Rosen] Add SparkContext.version to Python & Java [SPARK-1458]

core/src/main/scala/org/apache/spark/api/java/JavaSparkContext.scala

@@ -112,6 +112,9 @@ class JavaSparkContext(val sc: SparkContext) extends JavaSparkContextVarargsWork
 
   def startTime: java.lang.Long = sc.startTime
 
+  /** The version of Spark on which this application is running. */
+  def version: String = sc.version
+
   /** Default level of parallelism to use when not given by user (e.g. parallelize and makeRDD). */
   def defaultParallelism: java.lang.Integer = sc.defaultParallelism
 

python/pyspark/context.py

@@ -216,6 +216,13 @@ class SparkContext(object):
         SparkContext._ensure_initialized()
         SparkContext._jvm.java.lang.System.setProperty(key, value)
 
+    @property
+    def version(self):
+        """
+        The version of Spark on which this application is running.
+        """
+        return self._jsc.version()
+
     @property
     def defaultParallelism(self):
         """