jareware/viewports — pull request #2 by jvah (2014-10-07 12:49:57+00:00)
Title: Fix the index function use to work with new Sass versions.

On failure index returns now null instead of false, but viewports always
compares to false. This is easy to fix by taking a logical not of the resulting
value. For more information see https://github.com/sass/sass/issues/1127