Studio: renames nav dropdown pattern and corrects references

cms/static/sass/elements/_controls.scss

@@ -148,9 +148,9 @@
 // ====================
 
 // simple dropdown button styling - should we move this elsewhere?
-.btn-dd {
-  @extend .btn;
-  @extend .btn-pill;
+.ui-btn-dd {
+  @extend .ui-btn;
+  @extend .ui-btn-pill;
   padding:($baseline/4) ($baseline/2);
   border-width: 1px;
   border-style: solid;
@@ -158,7 +158,7 @@
   text-align: center;
 
   &:hover, &:active {
-    @extend .fake-link;
+    @extend .ui-fake-link;
     border-color: $gray-l3;
   }
 
@@ -169,8 +169,8 @@
 }
 
 // layout-based buttons - nav dd
-.btn-dd-nav-primary {
-  @extend .btn-dd;
+.ui-btn-dd-nav-primary {
+  @extend .ui-btn-dd;
   background: $white;
   border-color: $white;
   color: $gray-d1;

cms/static/sass/elements/_header.scss

@@ -75,7 +75,7 @@
 
     .title {
       @extend .t-action2;
-      @extend .btn-dd-nav-primary;
+      @extend .ui-btn-dd-nav-primary;
       @include transition(all $tmg-f2 ease-in-out 0s);
 
       .label, .icon-caret-down {