rft - pretty btns for stacktrace in testcases

![btn1](https://cloud.githubusercontent.com/assets/1964214/2840113/0f52035e-d050-11e3-86dd-f23552e68cfd.png)
![btn2](https://cloud.githubusercontent.com/assets/1964214/2840114/0f8f6104-d050-11e3-90c1-e17948d7da13.png)
![btn3](https://cloud.githubusercontent.com/assets/1964214/2840115/0f8f6c9e-d050-11e3-9e1a-c373d5d9f4b3.png)

instead of ugly link:
![btn4](https://cloud.githubusercontent.com/assets/1964214/2840140/6bb1a0d2-d050-11e3-90cf-8eb921293037.png)