Identity UI cleanup

This branch contains code for 3 changes:

 - Fixing the identity navigation menu (now looks nice and works on mobile).

 - Add legal text on sign in form and move legal text on register form to above button on smaller screens and to the right of the button on larger screens.

 - Adding tab ordering to signin and registration pages.

The changes are grouped together in this branch as they are all part of a christmas cleanup of some longstanding identity ui issues.

![code-13](https://f.cloud.github.com/assets/1170410/1858916/82c3e73c-7798-11e3-9607-2ef15b5b0e00.gif)