Added transform-style mixin
Honor $asset-pipeline argument when emitting 1x background-image
Update app/assets/stylesheets/addons/_hide-text.scss

Hiding the text has nothing to do with the background or the border.
Merge branch 'transform-style'
Merge pull request #188 from floptwo/patch-1

Hide-text mixin should not override background and border
Removed box-shadow mixin from button addon
Merge pull request #183 from mbrictson/retina-image-fix

Honor $asset-pipeline argument when emitting 1x background-image
Version bump to 3.1.1
Update readme.md

Fixed the broken logo image.
Add Placeholder support for firefox 19+
Add helper for prefixed backface-visibility property
Update linear-gradient mixin to spec
Extracted function to helper file. Make linear-gradient function work to spec. WIP
Bring radial-gradient function and mixin up to spec
Make background-shorthand mixin play well with the new gradient changes
Finished gradients updates to spec. Refactored helper functions to helpers directory
Fix bug in sass prefixer
Depreacted background-size mixin
Remove ms vendor prefix from keyframes mixin
Removed some prefixes and other cleanup