Use HTML5 + some tweaks

- make code valid
- fix formatting
- use higher resolution images
- some cleanup
Use HTML5

- make code valid
- fix formatting
- use higher resolution images
- some cleanup

Before: http://www.clockworkmod.com/superuser/install.html
After: http://jackmu95.de/superuser/install.html
Merge pull request #1 from jackmu95/master

Use HTML5