Invalidate reader meta data on flush.
Merge pull request #1067 from tweise/hds

Invalidate reader meta data on flush.
Housekeeping.
Merge branch 'hds' of https://github.com/DataTorrent/Malhar into hds
Single port partitioned operator abstraction.
File index rewrite bug.
Merge pull request #1068 from tweise/hds

Single port partitioned operator abstraction.
Replace byte[] with Slice for keys.
Merge branch 'hds' of https://github.com/DataTorrent/Malhar into hds
Override not needed.
Merge branch 'hds' into generichds