fix 'mixed content' error

Author: totalamd

demo/lint.html

@@ -9,9 +9,9 @@
 <script src="../lib/codemirror.js"></script>
 <script src="../mode/javascript/javascript.js"></script>
 <script src="../mode/css/css.js"></script>
-<script src="https://cdnjs.cloudflare.com/ajax/libs/jshint/2.9.5/jshint.min.js"></script>
-<script src="https://rawgithub.com/zaach/jsonlint/79b553fb65c192add9066da64043458981b3972b/lib/jsonlint.js"></script>
-<script src="http://csslint.net/js/csslint.js"></script>
+<script src="//cdnjs.cloudflare.com/ajax/libs/jshint/2.9.5/jshint.min.js"></script>
+<script src="//rawgithub.com/zaach/jsonlint/79b553fb65c192add9066da64043458981b3972b/lib/jsonlint.js"></script>
+<script src="//csslint.net/js/csslint.js"></script>
 <script src="../addon/lint/lint.js"></script>
 <script src="../addon/lint/javascript-lint.js"></script>
 <script src="../addon/lint/json-lint.js"></script>