Rename LTR mixins

sass/components/modal.sass

@@ -63,7 +63,7 @@ $modal-card-body-padding: 20px !default
   background: none
   height: $modal-close-dimensions
   position: fixed
-  right: $modal-close-right
+  +ltr-position($modal-close-right)
   top: $modal-close-top
   width: $modal-close-dimensions
 
@@ -102,7 +102,7 @@ $modal-card-body-padding: 20px !default
   border-top: $modal-card-foot-border-top
   .button
     &:not(:last-child)
-      margin-right: 0.5em
+      +ltr-property("margin", 0.5em)
 
 .modal-card-body
   +overflow-touch