Get rid of negative margins on flex elements

[snide]

I fight this stuff every day. While negative margins make some of hte sass calculations easier, they really mess up anytime a flexgroup or grid is in a container with fixed sizes. Biggest problem is that overflows will trigger because the element is shifted outside of a container because it's a negative margin.

[cchaos]

Another problem is that it can cause an overlap of clickable elements

[chandlerprall]

Closing this, it is implied by any solution found in #55