Add Apache license headers and LICENSE and NOTICE files

LICENSE

NOTICE

bagel/pom.xml

bagel/src/main/scala/spark/bagel/Bagel.scala

...l/src/main/scala/spark/bagel/examples/PageRankUtils.scala

...c/main/scala/spark/bagel/examples/WikipediaPageRank.scala

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

bagel/src/test/resources/log4j.properties

bagel/src/test/scala/bagel/BagelSuite.scala

bin/slaves.sh

bin/spark-config.sh

bin/spark-daemon.sh

bin/spark-daemons.sh

bin/start-all.sh

bin/start-master.sh

bin/start-slave.sh

bin/start-slaves.sh

bin/stop-all.sh

bin/stop-master.sh

bin/stop-slaves.sh