Refactored EventReplayer.collectJobRDDs
Bug fix: RDDs may be recorded multiple times
Removed RDD.dependenciesUpdated and EventReplayer assertion support
Fix compilation failure
Added preCompute and postCompute hooks in RDD
Implemented assertForall and assertExists with RDD.postCompute
Refactored EventLoggingSuite
Synchronized EventReplayer.stream field
Reimplemented assertForall & assertExists
Added test cases for assertForall and assertExists
Minor refactoring