Link fixes

- Create Class Fail page had the wrong create instructor link and layout
was different from Create Class
- Create Class Success page had wrong create instructor link
- Register Student, Fail, and Success "Back" button went to login page,
now is a "Clear" button that goes to Register Student
- Register Student Fail and Success didn't exist anymore, now do
- Tweaked .home_button to have the button be the size of the hover
effect and the hover effect to be same color as nav hover effect