WEB UI: add icon for button in windows add

http://www.softicons.com/toolbar-icons/flatastic-icons-part-1-by-custom-icon-design/cancel-icon

src/webui/static/app/ext.css

@@ -494,6 +494,10 @@
     background-image: url(../icons/bouquets.png) !important;
 }
 
+.cancelButton{
+    background-image: url(../icons/cancel_button.png) !important;
+}
+
 .x-linked {
     display: inline-block;
     background-image: url(../icons/linked.gif) !important;

src/webui/static/app/idnode.js

@@ -823,6 +823,7 @@ tvheadend.idnode_create = function(conf, onlyDefault)
     var saveBtn = new Ext.Button({
         tooltip: 'Create new entry',
         text: 'Create',
+        iconCls: 'add',
         hidden: true,
         handler: function() {
             var params = conf.create.params || {};
@@ -843,6 +844,7 @@ tvheadend.idnode_create = function(conf, onlyDefault)
     var undoBtn = new Ext.Button({
         tooltip: 'Cancel operation',
         text: 'Cancel',
+        iconCls: 'cancelButton',
         handler: function() {
             win.close();
         }