No need to, we are doing the maths!

The rest of the code expects bgColour to be a string

Everything else expects them as %.  Also, rework to reduce rounding problems.

Take this structure of backgrounds for example, 1 being the closest element:
1. rgba(10,10,10, .5);
2. rgba(10,10,50, .1);
3. rgb(10,10,250);

We need to transform background 2 into a solid color before we transform background 1 into a solid colour.

This follows the test procedure from http://www.w3.org/TR/2014/NOTE-WCAG20-TECHS-20140408/F68

We can't reliably compute the contrast of text over a background if the text is absolutely positioned over the background of another element that isn't a direct parent of the text element.

Make absolutely positioned contrast errors warnings

Conflicts:
	Standards/WCAG2AAA/Sniffs/Principle1/Guideline1_4/1_4_3_Contrast.js

was causing an error

Only push an error if `warning === false`

Merge with HTML_Codesniffer

Don't process the element if no body was could be found.
This was causing a fatal js error.

Don't try to check SVG objects

Merge with upstream

Conflicts:
	Standards/WCAG2AAA/Sniffs/Principle1/Guideline1_4/1_4_3_Contrast.js
	Standards/WCAG2AAA/Sniffs/Principle4/Guideline4_1/4_1_2.js

Merge with upstream

This was throwing a false positive in some cases, where it should trigger a manual check instead.

…form

Check for the will-change: 'transform' background image performance hack

Merge with upstream

form controls don't need labels if they are display:none