Add collaborator now handles roles, added macaron-binding for binding and validation

src/css/less/tightform.less

@@ -23,6 +23,10 @@
   }
 }
 
+.tight-form-btn {
+  padding: 8px 12px;
+}
+
 // old graphite-segment-list
 .tight-form-list {
   list-style: none;