Add IRC hooks for opened pull requests

[brson]

servo shows new pull requests and that's pretty nice. Could be useful for #rust too. script

[bstrie]

So is the idea to just run that script once, on any machine, and it will tell Github that we want that particular irc channel to get updates on pulls?

[brson]

I think so, but please don't do it without consensus.

[brson]

I'm not entirely sure we want this since we have a lot of eyes on pull requests already.

[bstrie]

I think this is unnecessary now that we have http://buildbot.rust-lang.org/bors/bors.html for keeping track of PRs. Reopen if you feel otherwise.