Merge branch 'http-repl-class-serving'

Makefile

run

src/scala/spark/Executor.scala

src/scala/spark/repl/ClassServer.scala

src/scala/spark/repl/ExecutorClassLoader.scala

src/scala/spark/repl/SparkInterpreter.scala

...ty/jetty-7.1.6.v20100715/jetty-server-7.1.6.v20100715.jar

third_party/jetty-7.1.6.v20100715/servlet-api-2.5.jar