Remove old styles for IE7 and below

Those browsers are old, forgotten, and aren't used anymore anyway. And the
website probably doesn't work in those old browsers anyway.
add headers.README
Merge pull request #200 from aykevl93/drop-ie7-styles

Verwijder IE7-specifieke CSS
Use `utf-8` instead of `utf8`. This fixes a problem with IE9

`utf8` is non-standard, but is accepted by most other browsers. `utf-8` it shall
be.
Merge pull request #205 from aykevl93/fix-invalid-charset

Use `utf-8` instead of `utf8`. This fixes a problem with IE9