Add WebSocket support

[jlouvel]

• expose as an extra protocol, in a REST-compatible way
• let developers reuse existing server resources
• similar to W3C Server-Sent Events approach

Suggested by Olivier Croisier

workload: 2d (seems well documented, perhaps have a first step of analysis, before estimating the workload)

[jlouvel]

References:

• Websockets API in Java EE: http://docs.oracle.com/javaee/7/tutorial/doc/websocket.htm
• JSR 356: https://jcp.org/en/jsr/detail?id=356
  • http://www.oracle.com/technetwork/articles/java/jsr356-1937161.html
• http://java-websocket.org/
• Atmosphere

[OlivierCroisier]

A Sock.js-compatible module would be nice : https://github.com/sockjs
Also, maybe add support for STOMP to format websocket messages ?

[jlouvel]

Good ideas, thanks Olivier.

Here is a pointer to STOMP
http://jmesnil.net/stomp-websocket/doc/