fix: LibSass 3.5.4 inspect() bug

inspect() function should return an unquoted string when passed a
quote string - sass/libsass#2826

This bug has been fixed in LibSass 3.6.0 - unfortunatelly node-sass its
having issues updating to 3.6.0
(sass/node-sass#2685)
While we wait for node-sass. We need to make sure that values that we
pass to the utilities mixins are exactly as described in _system-tokens.scss

src/stylesheets/components/_tile.scss

@@ -3,7 +3,7 @@
 
 .sds-tile {
   @include u-display('inline-block');
-  @include u-margin-x('2');
+  @include u-margin-x(2);
 }
 
 .sds-tile__content {
@@ -39,7 +39,7 @@
   @media only screen and (max-width: 600px) {
     .sds-tile__icon {
       @include u-display('inline-block');
-      @include u-margin-right('2');
+      @include u-margin-right(2);
       @include u-text('secondary');
       height: 30px;
       width: 30px;
@@ -68,7 +68,7 @@
 .sds-tile__content.sds-tile--outline {
   @include u-border(2px, 'white');
   @include u-radius('lg');
-  @include u-padding('2');
+  @include u-padding(2);
   background: rgba(240, 245, 249, 0.95);
   text-decoration: none !important;
   height: 150px;
@@ -95,15 +95,15 @@
 @media only screen and (max-width: 600px) {
   .sds-tile {
     @include u-display('block');
-    @include u-margin-y('1');
+    @include u-margin-y(1);
   }
 
   .sds-tile__content,
   .sds-tile__content.sds-tile--outline {
     @include u-display('flex');
     @include u-flex('row');
-    @include u-padding-y('0');
-    @include u-padding-x('2');
+    @include u-padding-y(0);
+    @include u-padding-x(1);
     height: 50px;
     width: 300px;
   }

src/stylesheets/elements/_buttons.scss

@@ -341,7 +341,7 @@
   @include u-display('flex');
   @include u-bg('white');
   @include u-flex('justify-center');
-  @include u-margin('1');
+  @include u-margin(1);
 
   span {
     font-size: 14px;