[lint demo] Remove css lint example

Since the only pre-build version of csslint was changed to some
global-scope-polluting mess that breaks our module loader headers.

Issue #4123

demo/lint.html

@@ -11,11 +11,9 @@
 <script src="../mode/css/css.js"></script>
 <script src="//ajax.aspnetcdn.com/ajax/jshint/r07/jshint.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="../addon/lint/lint.js"></script>
 <script src="../addon/lint/javascript-lint.js"></script>
 <script src="../addon/lint/json-lint.js"></script>
-<script src="../addon/lint/css-lint.js"></script>
 <style type="text/css">
       .CodeMirror {border: 1px solid black;}
     </style>
@@ -85,66 +83,6 @@ <h2>Linter Demo</h2>
 ]
 </textarea></p>
 
-    <p><textarea id="code-css">@charset "UTF-8";
-
-@import url("booya.css") print, screen;
-@import "whatup.css" screen;
-@import "wicked.css";
-
-/*Error*/
-@charset "UTF-8";
-
-
-@namespace "http://www.w3.org/1999/xhtml";
-@namespace svg "http://www.w3.org/2000/svg";
-
-/*Warning: empty ruleset */
-.foo {
-}
-
-h1 {
-    font-weight: bold;
-}
-
-/*Warning: qualified heading */
-.foo h1 {
-    font-weight: bold;
-}
-
-/*Warning: adjoining classes */
-.foo.bar {
-    zoom: 1;
-}
-
-li.inline {
-    width: 100%;  /*Warning: 100% can be problematic*/
-}
-
-li.last {
-  display: inline;
-  padding-left: 3px !important;
-  padding-right: 3px;
-  border-right: 0px;
-}
-
-@media print {
-    li.inline {
-      color: black;
-    }
-}
-
-@page {
-  margin: 10%;
-  counter-increment: page;
-
-  @top-center {
-    font-family: sans-serif;
-    font-weight: bold;
-    font-size: 2em;
-    content: counter(page);
-  }
-}
-</textarea></p>
 <script>
   var editor = CodeMirror.fromTextArea(document.getElementById("code-js"), {
     lineNumbers: true,
@@ -160,12 +98,6 @@ <h2>Linter Demo</h2>
     lint: true
   });
 
-  var editor_css = CodeMirror.fromTextArea(document.getElementById("code-css"), {
-    lineNumbers: true,
-    mode: "css",
-    gutters: ["CodeMirror-lint-markers"],
-    lint: true
-  });
 </script>
 
   </article>