Make WebSocket encrypt setting default to page protocol.

I.e. if the page is https:// then the WebSocket encrypt setting will
default to wss:// (TLS encryption).

Note that since noVNC settings are saved in cookies, this will only
affect first load. If you have already loaded the page, then the
encrypt setting will be whatever you last set it to.

include/ui.js

@@ -48,7 +48,7 @@ load: function() {
     UI.initSetting('host', '');
     UI.initSetting('port', '');
     UI.initSetting('password', '');
-    UI.initSetting('encrypt', false);
+    UI.initSetting('encrypt', (window.location.protocol === "https:"));
     UI.initSetting('true_color', true);
     UI.initSetting('cursor', false);
     UI.initSetting('shared', true);

vnc_auto.html

@@ -101,7 +101,8 @@
             }
 
             rfb = new RFB({'target':       $D('noVNC_canvas'),
-                           'encrypt':      WebUtil.getQueryVar('encrypt', false),
+                           'encrypt':      WebUtil.getQueryVar('encrypt',
+                                    (window.location.protocol === "https:")),
                            'true_color':   WebUtil.getQueryVar('true_color', true),
                            'local_cursor': WebUtil.getQueryVar('cursor', true),
                            'shared':       WebUtil.getQueryVar('shared', true),