DAR-826: implement fluid image layout with a single, unchanged background image. Still needs tweaks for the max width breakpoint.
DAR-826: fix layout not being centered after max width.
DAR-826: general cleanup and fixes for any solution.
DAR-826: fix fluid background after max width has been met.
DAR-826: fix jumpy transitions.
DAR-826: don't switch between background images on body and body:after/:before -- it causes flickering in some browsers.
DAR-826: add bourbon Sass library.
DAR-826: add the background gradient.
DAR-826: add TODO note about gradient.
DAR-826: don't apply background-image-gradient to tiled backgrounds.
DAR-826: fix background gradient appearing too early.
DAR-826: fix background flicker for small screens.
DAR-825: fix placement of background image gradient so that it works nicely at any viewport size. Also renamed some of the width vars to offset so it's more explicit what they do.
DAR-826, send wiki bg image width and height as command line params to sass
DAR-826, fix inconsistent quotes and new lines
DAR-826, fix typo
Merge pull request #1040 from Wikia/DAR-826_sass_vars

DAR-826: send wiki bg image width and height as command line params to sass
DAR-826: disable fluid width background if there is no background image or it's tiled.
DAR-826: whitespace cleanup.
DAR-826: disable fluid width background image handling for images less wide than the default skin width (these images are left aligned by default).