Bumped up document version to 0.5.3
Modifies for deprecating documents for CDH4.
Revised on EMR documents.
Merge branch 'doc-053' into 0.5-develop
Supports data header of Direct I/O TSV.
Merge remote-tracking branch 'private/directio-tsv-header' into 0.5-develop
Revised Direct I/O compress description.