Test sass 3.1 through 3.4
Add sass Gemfiles to travis configuration
Support old find_real_file arguments
Wrap existing engine with erb
Merge pull request #289 from rails/test-sass-versions

Improve Sass version coverage
Add back deprecated .css extension

Reverts d355de9b5aa8b79576c9afcadb58ebe164155861
Add deprecation notice
Merge pull request #291 from rails/deprecated-extra-css-ext

Deprecated .css.scss extension
Use context from options