Based on CSS Tricks: Using Flexbox - http://css-tricks.com/using-flexbox/ &
Special Thanks to Hugo Giraudel- http://hugogiraudel.com/2013/07/15/understanding-sass-lists/
Flexbox with elegant depreciation. Works in IE10+, iOS 6-, Safari 3.1-6, Firefox 20-, Chrome, Opera 12.1
Needs a good set of calculations for a reusable mixin.