[Fixes #1541] Disabled button beyond screen bounds

Fixes Issue #1541 — Settings > Indices disabled button expands beyond bounds on mobile.

This is done by saying that devices smaller than 768px should use `white-space: normal;` instead of `white-space: nowrap`.

Example Screenshot:
![screen shot 2014-10-07 at 9 22 17 am](https://cloud.githubusercontent.com/assets/947110/4542744/00a090b6-4e25-11e4-8b8f-b959d0e2671d.png)