Implement permessage-deflate extension

[meetmangukiya]

Might not be the best implementation..

1. I have processed only Binary, Text and Continuation frames in incoming frames
2. Processed all the outgoing frames

Using websocket-extensions is gonna make it easier to hook any extension in here!

I have tested it against a permessage-deflate server.

[rgillan]

I would want to see this load tested (very high load like 32k clients per server) if at all possible. About 12 months ago we tried to run perMessageDeflate using the ws module but it tanked the server side performance. We decided not to pursue pmd as we couldn't get the cpu resource usage under control with a very busy server. We run msgpack over binary frames which gives us typically about a 20-30% reduction in ota bandwidth with little or no client/server performance hit