Smaller settings and search result tab icons.

Shrink the tab icons slightly so they fit nicely within the smaller unity tabs.

Before:
![unity-before](https://cloud.githubusercontent.com/assets/122102/3678645/6e0b8bac-129c-11e4-91e8-bc3ff2d79eb3.png)

After:
![unity-after](https://cloud.githubusercontent.com/assets/122102/3678644/6e077cd8-129c-11e4-85c5-898d894e2a20.png)