Fix background-size hack on contain and cover values
Update dependencies
Release 2.1.1 version
README.md: Added the Visual Studio section and updated ASP.NET section
Merge pull request #281 from Taritsyn/master

README.md: Added the Visual Studio section and updated ASP.NET section
Clean up README.md
Allow to disable Autoprefixer by control comment
Remove old deprecated option and method
Move to unreleased PostCSS 2.0
Replace strict mode to safe