add license for responsive and rebuild

docs/assets/css/bootstrap-responsive.css

+/*!
+ * Bootstrap Responsive v2.0.0
+ *
+ * Copyright 2012 Twitter, Inc
+ * Licensed under the Apache License v2.0
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Designed and built with all the love in the world @twitter by @mdo and @fat.
+ */
 .hidden {
   display: none;
   visibility: hidden;

less/responsive.less

+/*!
+ * Bootstrap Responsive v2.0.0
+ *
+ * Copyright 2012 Twitter, Inc
+ * Licensed under the Apache License v2.0
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Designed and built with all the love in the world @twitter by @mdo and @fat.
+ */
+
 // Responsive.less
 // For phone and tablet devices
 // -------------------------------------------------------------
@@ -203,7 +213,7 @@
     .gridColumn() {
       float: left;
       margin-left: @gridGutterWidth;
-    } 
+    }
     [class*="span"] {
       .gridColumn();
     }
@@ -436,7 +446,7 @@
     .gridColumn() {
       float: left;
       margin-left: @gridGutterWidth;
-    } 
+    }
     [class*="span"] {
       .gridColumn();
     }