Initial work on making stuff compile with protobuf Mesos

core/lib/mesos.jar

core/lib/protobuf-2.3.0.jar

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

core/src/main/scala/spark/HadoopFile.scala

core/src/main/scala/spark/Job.scala

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

core/src/main/scala/spark/ParallelArray.scala

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

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

core/src/main/scala/spark/Task.scala

run