Remove E4X dependency from KeySnail plugin system

Since Mozilla plan to remove E4X from their systems completely (WTF?),
we remove E4X dependency from KeySnail plugin system with this commit.

For plugin developers:

Don't too worry about compatibility issues. Based on a dirty
hack (script-rewriting), *KeySnail still allows you to use XML literal
to express PLUGIN_INFO*. Note that you cannot use most of wonderful
E4X features include expression-expansion, various query expressions,
and so forth.

R.I.P E4X.

content/installplugindialog.js

@@ -1,28 +1,19 @@
 var ksInstallPluginDialog = function () {
     var modules;
 
-    var dom;
+    var elementContainer;
     var pluginPath;
 
-    var defaultIconURL = "chrome://keysnail/skin/script.png";
-
     function setInfo() {
-        var xml = window.arguments[0].xml;
+        var pluginInfo = window.arguments[0].pluginInfo;
 
-        if (!xml)
+        if (!pluginInfo)
             return;
 
-        function setAttributeFromXml(destination, attribute, xml) {
-            destination.setAttribute(attribute, modules.util.xmlGetLocaleString(xml));
-        }
-
-        setAttributeFromXml(dom["plugin-info-name"]        , "value", xml.name);
-        setAttributeFromXml(dom["plugin-info-description"] , "value", xml.description);
-        setAttributeFromXml(dom["plugin-info-version"]     , "value", xml.version);
-
-        dom["plugin-info-icon"].setAttribute("src",
-                                             modules.util.xmlGetLocaleString(xml.iconURL) ||
-                                             defaultIconURL);
+        elementContainer["plugin-info-name"].setAttribute("value", pluginInfo.name);
+        elementContainer["plugin-info-description"].setAttribute("value", pluginInfo.description);
+        elementContainer["plugin-info-version"].setAttribute("value", pluginInfo.version);
+        elementContainer["plugin-info-icon"].setAttribute("src", pluginInfo.iconURL);
     }
 
     function createScriptItem(aURL) {
@@ -49,22 +40,19 @@ var ksInstallPluginDialog = function () {
     }
 
     function setScriptList() {
-        var xml       = window.arguments[0].xml;
-        var pluginURL = window.arguments[0].pluginURL;
+        var pluginInfo = window.arguments[0].pluginInfo;
+        var pluginURL  = window.arguments[0].pluginURL;
 
-        if (!xml)
+        if (!pluginInfo)
             return;
 
         var item;
 
-        dom["plugin-script-list"].appendChild(
-            createScriptItem(pluginURL));
+        elementContainer["plugin-script-list"].appendChild(createScriptItem(pluginURL));
 
-        for (let [, script] in Iterator(xml.require.script))
-        {
-            dom["plugin-script-list"].appendChild(
-                createScriptItem(script.text()));
-        }
+        pluginInfo.requiredScripts.forEach(function (scriptURL) {
+            elementContainer["plugin-script-list"].appendChild(createScriptItem(scriptURL));
+        });
     }
 
     var self = {
@@ -78,13 +66,11 @@ var ksInstallPluginDialog = function () {
                        "plugin-info-description",
                        "plugin-script-list",
                        "plugin-info-version"];
-            dom = new Object();
+            elementContainer = new Object();
 
-            ids.forEach(
-                function (id) {
-                    dom[id] = document.getElementById(id);
-                }
-            );
+            ids.forEach(function (id) {
+                elementContainer[id] = document.getElementById(id);
+            });
 
             pluginPath = window.arguments[0].pluginPath;
             setInfo();
@@ -114,8 +100,8 @@ var ksInstallPluginDialog = function () {
 }();
 
 (function () {
-     var wm = Components.classes["@mozilla.org/appshell/window-mediator;1"]
-         .getService(Components.interfaces.nsIWindowMediator);
-     var browserWindow = wm.getMostRecentWindow("navigator:browser");
-     ksInstallPluginDialog.modules = browserWindow.KeySnail.modules;
- })();
+    var wm = Components.classes["@mozilla.org/appshell/window-mediator;1"]
+            .getService(Components.interfaces.nsIWindowMediator);
+    var browserWindow = wm.getMostRecentWindow("navigator:browser");
+    ksInstallPluginDialog.modules = browserWindow.KeySnail.modules;
+})();

content/keysnail.js

@@ -630,7 +630,7 @@
                 userscript.installPluginAndRequiredFiles({
                     name           : util.getLeafNameFromURL(util.pathToURL(script.path)),
                     code           : script.code,
-                    info           : script.info,
+                    pluginInfo     : script.pluginInfo,
                     forceOverWrite : true,
                     next           : function (succeeded) {
                         if (typeof next === "function")