added retina-image mixin
Added optional retina-filename
Added asset-pipeline support for rails
Replaced media-query with hidpi mixin
Removed image-height and width in favor of background-size variable
dont impose 2x naming for custom retina-filenames
Added unpack function
Updated position mixin to use unpack function on coordinates parameter
Updated position mixin to ignore falsy values
Change false values to null to deprecate compact function
Remove deprecated webkit-gradient code
Removed unneeded compact function
Merge branch 'deprecate-webkit-gradient'
Fix merge conflicts. Added custom retina suffix.
Added strip-units function. Make the px-to-em function accept unitless or values with units.
Border-image fix for firefox
Rename retina-image variable
Fix transition defaults to work with firefox22+
Added settings section. Added global -base variable to px-to-em mixin
Remove opera prefix from the keyframes mixin