I was torn between including the
sticky-footer mixin and the mixins for stretching elements to fit their containing parent element. In the end I've decided not to include them, the reason being, they are all hacks to solve problems that have since been solved by Flexbox in much simpler and cleaner ways, especially the
sticky-footer mixin, which even requires additional HTML to be included for it to work.
I'm not saying they're bad. Each of these mixins offers brilliant and useful solutions to these problems. However, Flexbox has completely removed the necessity for these mixins. For that reason I've decided not to cover the sticky footer or stretching mixins.
I also left out the spriting features in Compass ...