Made EventLogInputStream & EventLogOutputStream class classes
Added a feature incomplete EventReplayer
Minor reformatting
Try our best to let the replayer see the most recent events
Bug fix: InputStream.available() not working as expected, this fix is a workaround, should investigate later
Added new test case for EventReplayer
Call `RDD.depencencies` when serializing RDD objects to serialize ensure their dependencies are also serialized
Added SparkContext.removeSparkListener
Added test case to ensure RDDs are properly restored from event log
Added RDD dependencies for the test case in the last commit
Updated EventReplayer: provide more user-friendly error message
New test case for cross-session event log replay
Added test case for EventReplayer.visualizeRDDs()