Added bootstap and testing carousel

_sass/bootstrap/mixins/_size.scss

@@ -0,0 +1,10 @@
+// Sizing shortcuts
+
+@mixin size($width, $height) {
+  width: $width;
+  height: $height;
+}
+
+@mixin square($size) {
+  @include size($size, $size);
+}