Added legal information to the code samples CSS

docs/code.css

@@ -1,3 +1,21 @@
+/*
+ * This file is part of b6b.
+ *
+ * Copyright 2017 Dima Krasner
+ *
+ * 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.
+ */
+
 .hljs-keyword, .hljs-literal, .hljs-built_in, .hljs-variable, .hljs-type {
 	color: #333;
 	font-weight: normal;