JERSEY-2010: Code cleaning before merging the Pull Request 23 (HttpDigestAuthFilter)
         - Added javadocs, code cleaning
         - DigestScheme is passed to subsequent filter in the header instead of cache
         - Unnecessary response entity buffering removed

Change-Id: I7c25aa93f62612f1b1b54412ec3aa1c43694b4ae
Merge "JERSEY-2010: Code cleaning before merging the Pull Request 23 (HttpDigestAuthFilter)          - Added javadocs, code cleaning          - DigestScheme is passed to subsequent filter in the header instead of cache          - Unnecessary response entity buffering removed"