This was causing very tall lines on many websites. We can now see the
section header thingy on google.com (although it's broken into lines
where it should not be..) :^)
As suggested by @awesomekling in a code review and (initially) ignored
by me :^)
Implementation is roughly based on LibJS's trim_string(), but with a fix
for trimming all-whitespace strings.
Many properties can now have percentage values that get resolved in
layout. The reference value (what is this a percentage *of*?) differs
per property, so I've added a helper where you provide a reference
value as an added parameter to the existing length_or_fallback().
This momentarily handles the CSS property "position: absolute;" in
combination with the properties "top" and "left", so that elements can
be placed anywhere on the page independently from their parents.
Statically positioned elements ignore absolute positioned elements when
calculating their position as they don't take up space.
