Make use of +fullhd mixin for columns (#815)

Proposed fix for https://github.com/jgthms/bulma/issues/814

sass/grid/columns.sass

@@ -202,6 +202,43 @@
         width: ($i / 12) * 100%
       &.is-offset-#{$i}-widescreen
         margin-left: ($i / 12) * 100%
+  +fullhd
+    &.is-narrow-fullhd
+      flex: none
+    &.is-full-fullhd
+      flex: none
+      width: 100%
+    &.is-three-quarters-fullhd
+      flex: none
+      width: 75%
+    &.is-two-thirds-fullhd
+      flex: none
+      width: 66.6666%
+    &.is-half-fullhd
+      flex: none
+      width: 50%
+    &.is-one-third-fullhd
+      flex: none
+      width: 33.3333%
+    &.is-one-quarter-fullhd
+      flex: none
+      width: 25%
+    &.is-offset-three-quarters-fullhd
+      margin-left: 75%
+    &.is-offset-two-thirds-fullhd
+      margin-left: 66.6666%
+    &.is-offset-half-fullhd
+      margin-left: 50%
+    &.is-offset-one-third-fullhd
+      margin-left: 33.3333%
+    &.is-offset-one-quarter-fullhd
+      margin-left: 25%
+    @for $i from 1 through 12
+      &.is-#{$i}-fullhd
+        flex: none
+        width: ($i / 12) * 100%
+      &.is-offset-#{$i}-fullhd
+        margin-left: ($i / 12) * 100%
 
 .columns
   margin-left: -0.75rem