Also remove the calls to measure each <li>, which was probably causing
havoc in safari. Affects #25 and #42

Faster and more accurate to use inner/outer width. Also reduces number
of measurements. Affects #25 and #42

Take into account the padding on the left side of navigation area.

This file is not needed:
https://github.com/ebiwd/EBI-Pattern-library/issues/15

From web_guidelines git: 3047c8b ("/about/cookies, /about/privacy and /about/terms-of-use now rolled into single page by SMC: update footer and cookie banner", 2015-10-26)

For #32

For #32

For #38

For #20