Merge branch 'refs/heads/master' into ver3.1.4

* refs/heads/master:
  Update model.liquid
  Updated version number in index template
  Updated to match Bourbon v3.1.2.1 *see note*
Updated to match Bourbon v3.1.4 *see note*

**Notes**
3.1.3 and 3.1.4 contain bug fixes related to the newer linear-gradient mixin