Merge branch 'master' into mesos-0.9

...la/spark/bagel/examples/WikipediaPageRankStandalone.scala

core/src/main/scala/spark/BoundedMemoryCache.scala

core/src/main/scala/spark/Cache.scala

core/src/main/scala/spark/CacheTracker.scala

core/src/main/scala/spark/DiskSpillingCache.scala

core/src/main/scala/spark/Executor.scala

core/src/main/scala/spark/JavaSerializer.scala

core/src/main/scala/spark/KryoSerializer.scala

core/src/main/scala/spark/LocalScheduler.scala

core/src/main/scala/spark/MesosScheduler.scala

core/src/main/scala/spark/PipedRDD.scala

core/src/main/scala/spark/RDD.scala

core/src/main/scala/spark/Serializer.scala

core/src/main/scala/spark/SerializingCache.scala

core/src/main/scala/spark/SimpleJob.scala

core/src/main/scala/spark/SoftReferenceCache.scala

core/src/main/scala/spark/SparkEnv.scala

core/src/main/scala/spark/UnionRDD.scala

core/src/main/scala/spark/Utils.scala

core/src/main/scala/spark/WeakReferenceCache.scala