add licensing for buttons.less

less/buttons.less

@@ -1,3 +1,20 @@
+/**
+ *
+ * Copyright 2013 LinkedIn Corp. All rights reserved.
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ *     http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 div.hopscotch-bubble .hopscotch-nav-button {
   /* borrowed from katy styles */
   font-weight:bold;