Turn Get Started page's forms into `<form>`s and tweak styling

![screenshot 2014-02-27 21 30 35](https://f.cloud.github.com/assets/29096/2290528/61f380d4-a020-11e3-8f8c-c85182511b24.png)

![screenshot 2014-02-27 21 30 45](https://f.cloud.github.com/assets/29096/2290529/65e389f0-a020-11e3-9c27-41a7d5c42f5a.png)