Added Viewport Height & Width helpers

This allows the user to make a container (ideally) to use viewport height and width and allow better vertical/horizontal alignments of elements.

scss/utilities/_sizing.scss

@@ -10,3 +10,11 @@
 
 .mw-100 { max-width: 100% !important; }
 .mh-100 { max-height: 100% !important; }
+
+// Viewport additional helpers
+
+.min-vw-100 { min-width: 100vw !important; }
+.min-vh-100 { min-height: 100vh !important; }
+
+.vw-100 { width: 100vw !important; }
+.vh-100 { height: 100vh !important; }