Updated code to work with Nexus->Mesos name change

Makefile

run

src/scala/spark/Executor.scala

src/scala/spark/HdfsFile.scala

src/scala/spark/MesosScheduler.scala

src/scala/spark/ParallelArray.scala

src/scala/spark/RDD.scala

src/scala/spark/SparkContext.scala

src/scala/spark/Task.scala

third_party/mesos.jar

third_party/nexus.jar