add wxbutton to wxmobile

admin/templates/default/mb_special_item.edit.php

@@ -82,6 +82,7 @@
                     <option value="webview">网络页面</option>
                     <option value="video">外部视频链接</option>
                     <option value="audio">外部音频链接</option>
+                    <option value="wxbutton">微信原生按钮</option>
                 </select>
                 <input id="dialog_item_show_data" type="text" class="txt w200 marginright marginbot vatop"><br/>
                 <span id="dialog_item_image_desc" class="dialog-image-desc"></span>