[rest] Filter for gzip/deflate content encoding that wraps both input and output side

Review Request #1254 - Created Nov. 25, 2010 and submitted

Andrew Purtell
After HBASE-3275 the REST gateway uses Jetty's GzipFilter to will return gzip or deflate encoded content to the client if the client requested it using the appropriate Accept-Encoding header. However Jetty's GzipFilter only wraps output side processing.

This patch implements a filter that also wraps input side processing, so clients can submit compressed PUT or POST bodies.
New unit test, passes.
  1. Looks great! RB did show some white spaces added unnecessarily, I assume you could remove those on commit.