removing unnecessary neat helpers for sass compilation ease

apps/openassessment/xblock/static/sass/themes/edx/_utilities.scss

@@ -88,7 +88,6 @@ $f-serif: 'PT Serif', Cambria, Georgia, 'Times New Roman', Times, serif;
 $f-sans-serif: 'Open Sans','Helvetica Neue', Helvetica, Arial, sans-serif;
 
 // layout - grid
-@import "neat/neat-helpers";
 $max-width: 100%;
 $grid-columns: 12;
 $gutter: $baseline-v;

apps/openassessment/xblock/static/sass/xb/utilities/_variables.scss

@@ -14,7 +14,6 @@ $baseline-h: 40px;                                                  // horizonta
 // layout - grid (neat-based - http://neat.bourbon.io/)
 // --------------------
 // grid
-@import "neat/neat-helpers";
 $max-width: 100%;                                                   // http://gridcalculator.dk/#/1040/12/20/20
 $grid-columns: 12;                                                  // make grid 12 columns
 $column: $baseline-v;