Remove colour map support

It was broken and unused. Remove it so we can simplify the code.

vnc.html

@@ -11,9 +11,9 @@
     This file is licensed under the 2-Clause BSD license (see LICENSE.txt).
 
     Connect parameters are provided in query string:
-        http://example.com/?host=HOST&port=PORT&encrypt=1&true_color=1
+        http://example.com/?host=HOST&port=PORT&encrypt=1
     or the fragment:
-        http://example.com/#host=HOST&port=PORT&encrypt=1&true_color=1
+        http://example.com/#host=HOST&port=PORT&encrypt=1
     -->
     <title>noVNC</title>
 
@@ -221,9 +221,6 @@
                     <li>
                         <div class="noVNC_expander">Advanced</div>
                         <div><ul>
-                            <li>
-                                <label><input id="noVNC_setting_true_color" type="checkbox" checked /> True Color</label>
-                            </li>
                             <li>
                                 <label><input id="noVNC_setting_cursor" type="checkbox" /> Local Cursor</label>
                             </li>