Intermediate checkin
updated CodecFileAccumable to use a first class class for the Accumulator
Made CodecFileIterator an explicit class. Added close handling.
minor fixes (defensive code + efactoring) in reef-io file
mor erefactoring and defensive code in the CodecFileIterator
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into reef-bridge
Merge branch 'reef-bridge' of https://github.com/Microsoft-CISL/REEF into reef-bridge
Merge branch 'reef-bridge' of https://github.com/Microsoft-CISL/REEF into reef-bridge
improvement
0319 checkin
fix merge conflicts
call back to java