because sizing and positioning was a mess;
the follwing things are fixed with this:
- resizes and positions correctly according to html elements font-size
- IE11 compatiblity is now given
- a11y: expander is now correctly given a focus outline
- chevron is now coded into html instead of a css content value, which makes it easier to change (was an issue in the past)
- the visited checkmark now breaks correctly on long lines and hides behind the text if necessary
- some more css classes were introduced to make further extensions (eg. nested shortcut links) easier
