Improve accessibility

[Plebysnacc]

There is some issues to be fixed on our pages:

• checkboxes can not be triggered with ENTER
• Important Elements miss screenreader support

[dheidemann]

• just had a look on the checkboxes: for the checkboxes to be triggered by enter you need to initially reach them by tabbing through the form. But they aren't reachable (not a big problem from my perspective). What do you mean? What am I missing here?

• Which elements don't support screenreader?