turn signup links into signup buttons

before:
![image](https://cloud.githubusercontent.com/assets/273653/3788699/49ac3af8-1a72-11e4-8e84-513e78893945.png)


after:
![image](https://cloud.githubusercontent.com/assets/273653/3788701/505114aa-1a72-11e4-8580-cf9fac89d8e3.png)