added compass for sass compilation
use border-radius, box-shadow, text-overflow, background-clip without prefix
removed IE filter
short color codes
nesting of selectors
class variants using parent references (&)
removed unused chzn-results-scroll* classes
IE9 without gradients
sort properties using csscomb
Make use of image-url helper
Updated gruntfile and compass config
Merge pull request #1320 from koenpunt/css-to-sass

Use SASS for CSS generation.