Merge mfairchild365's contributions regarding absolute positioning (#99, unl#1) into master:

Make absolutely positioned contrast errors warnings.
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.

Conflicts:
	Standards/WCAG2AAA/Sniffs/Principle1/Guideline1_4/1_4_3.js
	Standards/WCAG2AAA/Sniffs/Principle1/Guideline1_4/1_4_3_Contrast.js
Remove trailing comma
Round of HTMLCS changes:

- If HTMLCS has any parse errors, such as if an included script had
  parse errors, PhantomJS should no longer hang.
Involved adding a fail callback path through HTMLCS, and some changes to
the PhantomJS side of things.
- Default PhantomJS runner now gives a summary at the end of the number of errors,
  warnings and notices.
- First stage of issue #107: Reworking of the "labels on inputs" testing
  in SC 1.3.1 to align with failure F68 changes in March 2014.
Attempt made on issue #79.

Select fields without a selected option now emit a warning instead of an
error. In HTML5 there is a defined value if none is selected; in HTML
4/XHTML 1.0 it is undefined, which means the message must still be
emitted.
Merge remote-tracking branch 'squizlabs/master'

Conflicts:
	Standards/WCAG2AAA/Sniffs/Principle1/Guideline1_4/1_4_3_Contrast.js
`msg` is already defined

was causing an error
Fix false positive

Only push an error if `warning === false`
Merge pull request #2 from mfairchild365/master

Merge with HTML_Codesniffer