Improve ClearFilter() Perfermance

[kent3513]

I got a performance issue on ClearFiliter(). I made a little change to improve it.
The original code will reset all node's title for clear as follow:

$.ui.fancytree._FancytreeClass.prototype.clearFilter = function(){
    this.visit(function (node) {
        delete node.match;
        delete node.subMatchCount;
        $(">span.fancytree-title", node.span).html(node.title);
        delete node.titleWithHighlight;
...
}

I add an if statement for reset the matched node's title. as follows:

$.ui.fancytree._FancytreeClass.prototype.clearFilter = function(){
    this.visit(function (node) {
        if (node.match)
        {
            $(">span.fancytree-title", node.span).html(node.title);
        }
        delete node.match;
        delete node.subMatchCount;
......