Update _grid.scss

add padding-right: 0; to m-all, t-all, d-all
Update comments.php

WordPress debugger sees an undefined constant is the callback function name isn't wrapped in single quotes. Doesn't affect operation of theme as far as I can tell, but WP unit testing suggests addressing these kinds of things.
Merge pull request #591 from PeterBeckley/patch-1

Update comments.php
Merge pull request #590 from oscom/patch-1

Update _grid.scss