Change newZlibEncoder factory to use jzlib implementation instead of jdk
implementation when windowSize or memLevel are different from the
default one.

Motivation:
WebSocket premessage-deflate extension needs to be sure of the
windowSize used.
Create distinct handler implementation for client and server.
Handle optional client_window_size and server_window_size parameters
during extension negociation.
Put back UTF8 checking and add a flag to disable it.
Rename WebSocketPremessageDeflateExtensionHandler to
WebSocketCompressionHandler in order to support more compression
extension in futur.