Fixed border-radius when only one button exists in a button-bar

Author: FabianAlbrecht

Diff for: scss/_button-bar.scss

@@ -26,7 +26,7 @@
 .button-bar > .button {
   @include flex(1);
   display: block;
-  
+
   overflow: hidden;
 
   padding: 0 16px;
@@ -51,4 +51,7 @@
     border-right-width: 1px;
     border-radius: 0px $button-border-radius $button-border-radius 0px;
   }
+  &:only-child {
+    border-radius: $button-border-radius;
+  }
 }