Compass mixins for the CSS4 `image-rendering` property with some cross-browser equivalents

_image-rendering.sass

=image-rendering($hint)

    @if $hint == 'crisp-edges'

		@if $legacy-support-for-ie8 or $legacy-support-for-ie7
			-ms-interpolation-mode: bilinear
		@if $experimental-support-for-webkit
			image-rendering: -webkit-optimize-contrast

		+experimental-value(image-rendering, crisp-edges, $moz: $experimental-support-for-mozilla, $webkit: false, $o: $experimental-support-for-opera, $ms : false, $khtml: false, $official: true)

	@else if $hint == 'pixelated'

		@if $legacy-support-for-ie8 or $legacy-support-for-ie7
			-ms-interpolation-mode: bilinear

		image-rendering: pixelated

	@else if $hint == 'optimizeQuality' or $hint == 'optimizeSpeed'

		@warn "#{$hint} is deprecated in CSS4 http://dev.w3.org/csswg/css-images/#the-image-rendering"

		image-rendering: $hint

	@else if $hint == 'auto'

		image-rendering: $hint

	@else

		@warn "'#{$hint} was ignored because it's not a valid property value for image-rendering (auto, crisp-edges, pixelated) http://dev.w3.org/csswg/css-images/#the-image-rendering"


=crisp-edges
	+image-rendering('crisp-edges')


=pixelated
	+image-rendering('pixelated')