Theme options to define layout grid breakpoints

[gaffkins]

It's nice to see options to change layout grid breakpoints.
Like:
/* increase the width of the grid lg and xl breakpoints /
$grid-breakpoints: (
lg: 1024px,
xl: 1366px
);
/ increase container width for the wider lg and xl breakpoints */
$container-max-widths: (
lg: 1050px,
xl: 1400px
);