createScreenshot() does not take into account window.devicePixelRatio

[mklepaczewski]

VisualCeption::createScreenshot() doesn't take into account window.devicePixelRatio and incorrectly calculates $coords, in particular when the screenshot is limited to a specific element.

[AdamOakman]

I can confirm there is indeed a problem in taking pictures for pixel ratio other than 1 - is there any chance for fixing it?