[themes] usability and accessibility improvement

[Egon Bianchet]

Hello, 
I'm wondering if there is a plan regarding usability and accessibility
of standard Drupal themes.

I'd like to know if somebody already thought about implementing:

- skip-navigation, return-to-top links
- change-font-size, high-contrast-css links
- internal, external and mailto links differentiation

-- 
Egon Bianchet <egon.bianchet at gmail.com>