+ recycle HttpRequestPacket/HttpResponsePacket in the AsyncHttpClientFilter, when we're sure nobody will try to touch them :)
Port Grizzly FeedableBodyGenerator changes from 1.7 to master.
- Fix redirect test.
- Update Grizzly provider to default back to the WorkerThreadIOStrategy.
- Removed SSL handshake logic from Grizzly's FeedableBodyGenerator.  It's not needed anymore since the handshake is forced when the connection is made.
Upgrade to Grizzly 2.3.6.
Set multiplier to two.
Don't apply outbound encodings.
Initial connection pool changes to support SPDY.
Remove tunnel establishment checks.  They are no longer needed as tunnelling is established when the connection is established.
HttpTransactionContext renamed to HttpTxContext.
Include a timeout on all Future.get() calls.
Reverting.
Refactoring in preparation for supporting spdy multiplexing.
Uptake grizzly 2.3.7-SNAPSHOT.  This release includes change necessary to support SPDY multiplexing with AHC.

Simple test of 20 concurrent requests over a single connection to https://www.google.com confirm multiplexing is working.
Drop Netty 3 support, move Spnego into api, close #316
Remove HttpContent and clean up Status, Headers and BodyParts
Minor clean up
Fix webdav test
Removed deprecated APIs
Port 169051cb72ff8487696cd7e19a20e3654f50fc49 on master