Select a node
zTree v3.x supports select multiple nodes.
Please use zTree object to executing the method.
JSON data object of the node to be selected.
Please ensure that this data object is an internal node data object in zTree.
addFlag = true means: append to select node, don't affect the previously selected node, can select multiple nodes.
addFlag = false means: select single node, prior the selected node is deselected.
If setting.view.selectedMulti = false, this para, this parameter is not valid, always select single node
no return value
var treeObj = $.fn.zTree.getZTreeObj("tree");
var nodes = treeObj.getNodes();
if (nodes.length>0) {
treeObj.selectNode(nodes[0]);
}