Show register and sign in buttons (bug 1072619)

https://bugzilla.mozilla.org/show_bug.cgi?id=1072619

![screen shot 2014-10-08 at 16 50 16](https://cloud.githubusercontent.com/assets/211578/4567872/367f94fa-4f35-11e4-9dc6-2cacf0ab9a36.png)
1140px wide

![screen shot 2014-10-08 at 16 50 42](https://cloud.githubusercontent.com/assets/211578/4567873/369a8e2c-4f35-11e4-95c7-4563575a7804.png)
768px wide

![screen shot 2014-10-08 at 16 50 55](https://cloud.githubusercontent.com/assets/211578/4567874/369a9d22-4f35-11e4-9bb5-3503614b1948.png)
320px wide

I can't make these buttons look like account settings at desktop width. I give up.
![screenshot 2014-10-09 11 35 56](https://cloud.githubusercontent.com/assets/211578/4580127/ccc76670-4fd2-11e4-898b-fa7b6d98c16b.png)
![screenshot 2014-10-09 11 35 59](https://cloud.githubusercontent.com/assets/211578/4580126/ccc525c2-4fd2-11e4-842c-9d41093c6968.png)