Add zindex to menu api

package.json

@@ -60,7 +60,7 @@
         "c9.ide.language.javascript.tern": "#a65ad88dd9",
         "c9.ide.language.javascript.infer": "#702bbd4dcd",
         "c9.ide.language.jsonalyzer": "#eaf8152b03",
-        "c9.ide.collab": "#6bec0da317",
+        "c9.ide.collab": "#38d942e50a",
         "c9.ide.local": "#2bfd7ff051",
         "c9.ide.find": "#989c06e6a7",
         "c9.ide.find.infiles": "#28b3cfcb47",

plugins/c9.ide.ui/menus.js

@@ -932,6 +932,7 @@ define(function(require, exports, module) {
             plugin.on("load", function(){
                 aml = new ui.menu({
                     id: options.id,
+                    zindex: options.zindex,
                     "onprop.visible" : function(e) {
                         emit(e.value ? "show" : "hide", lastCoords);
                         checkItems.call(this, e);
@@ -1032,6 +1033,12 @@ define(function(require, exports, module) {
                  * @readonly
                  */
                 get visible(){ return aml.visible; },
+                /**
+                 * Specifies the zindex of the menu
+                 * @property {Number} zindex
+                 */
+                get zindex(){ return aml && ui.getStyle(aml.$ext, "z-index"); },
+                set zindex(value) { aml && aml.setAttribute("zindex", value); },
                 /**
                  * The menu items appended to this menu
                  * @property {MenuItem[]} items