CCprogressTimer 初始值不爲0時，不顯示進度條

CCProgressTimer *ct = [CCProgressTimer progressWithFile@"progress.png"];
ct.postion = ccp(size.width/2, size.height);
ct.percentage = 50;
ct.type = kCCProgressTimerTypeHorizontalBarLR;
[self addChild:ct z:2];

初始值設置方式爲下下面的方式即可：percentage只能以增長的方式設置

ct.percentage = 0;

ct.percentage += 50;