Hidden overflow for long names on tag pages

small screens:
![](https://cloud.githubusercontent.com/assets/3798614/4515550/b7a3073a-4bc3-11e4-869e-74e0109a8bcd.png)
wide screens:
![](https://cloud.githubusercontent.com/assets/3798614/4515548/a733bc8c-4bc3-11e4-9f43-ba0f0bb45833.png)

Fixes #3926, closes #3975.