Add 'cboden/Ratchet' to dependencies.

# WebSockets #

I plan to use WebSockets in all situations, that require interaction with the MinePlus server, but should **not** create a http request.
And I imagine two situations, in which they would be helpful:
- Browser sends/receives chat messages
- Gameserver sends/receives events (e.g. player joins)

Using WebSockets here will replace [long-polling][1], but also force the server owner to open a new port **and** the user to use [a browser supporting WebSockets][2] .

## How it'll work  ##

*(We'll work in the `feature/websockets` branch)*

I'll continue here later :wink:.

[1]: http://en.wikipedia.org/wiki/Push_technology#Long_polling
[2]: http://caniuse.com/websockets