Have irc module be managed by npm instead of copying it

I found it curious that node-irc was copied into the Content directory, instead of having it managed by npm (which you are doing for express, socket.io, etc).  This commit just adds node-irc to package.json, so it is installed automatically when the user does `npm install`.

Feel free to ignore if there was a good reason why you did this (though I'd appreciate it if you let me know what that reason is).

Congrats on shipping your first nodejs app!