Added display classes per twbs#19343

Author: Teo Dell'Amico

scss/_utilities.scss

@@ -1,8 +1,9 @@
 @import "utilities/background";
 @import "utilities/clearfix";
+@import "utilities/display";
+@import "utilities/flex";
 @import "utilities/pulls";
 @import "utilities/screenreaders";
 @import "utilities/spacing";
 @import "utilities/text";
 @import "utilities/visibility";
-@import "utilities/flex";

scss/utilities/_display.scss

@@ -0,0 +1,13 @@
+//
+// Display utilities
+//
+
+.display-block {
+  display: block;
+}
+.display-inline-block {
+  display: inline-block;
+}
+.display-inline {
+  display: inline;
+}