Show pull request link, when commit related with pull request

![2014-10-27 4 19 06](https://cloud.githubusercontent.com/assets/683590/4785226/51eabd8c-5d77-11e4-8f86-8b0c8c7c2b4f.png)
![2014-10-27 4 19 18](https://cloud.githubusercontent.com/assets/683590/4785227/51f5437e-5d77-11e4-9d9d-e25a7e972e95.png)