Make $column and $gutter not use modular-scale

[kylefiedler]

The modular-scale functions are just complicating what is essentially a 3 to 1 ratio. Adding the function is unnecessarily complicating the code.

$column: 3em !default;
$gutter: 1em !default;

[tysongach]

👍 There’s been chatter about decoupling Bourbon from Neat. There’s only a few small functions and mixins from Bourbon that Neat uses, all them are non-essential (related PR). Removing modular-scale would be trivial.

[kennethormandy]

Really like this idea, and I’d be interested in helping. I was maintaining Straight Up, which was Neat without Bourbon, and it worked quite well. It’s nice to avoid the extra dependency if you’re using Autoprefixer.