CSS and HTML Fixes

### HTML
- Fixed header absolute links for `og:image` & `image_src`
- Fixed h3 on `sect2_aboutbody`
- Made one footer with 2 section instead of 1 section and a footer
(this fixes the big padding of the former last section)
- Removed uneeded comment about `tuktuk.min.js`

### CSS
- Moved `#clear` and `#clear2` to `custom.min.css` (Please do not edit
`tuktuk.min.css` since it's the framework and if we update it we will
lose your edit, use `custom.min.css` instead.)
- Fixed top left logo alignment on mobile device (now perfectly
centered.)