Added IRC build notification.

```
* travis-ci (~travis-ci@ec2-184-72-132-220.compute-1.amazonaws.com) has joined #scalaz
<travis-ci> [travis-ci] folone/scalaz#30 (scalaz-seven - cb5ee72 : folone): The build was fixed.
<travis-ci> [travis-ci] Change view : https://github.com/folone/scalaz/compare/8a884b7a1b45...cb5ee72c443d
<travis-ci> [travis-ci] Build details : http://travis-ci.org/folone/scalaz/builds/6076007
* travis-ci (~travis-ci@ec2-184-72-132-220.compute-1.amazonaws.com) has left #scalaz
```
[Description](http://about.travis-ci.org/docs/user/notifications/#IRC-notification). Presented configuration will only notify #scalaz@irc.freenode.net in case of a changing build state (was broken, got fixed or vice versa).

The downside is that it also sends notifications from all the forks, that have travis builds enabled (like it did from my fork up there ↑).