CCprogressTimer 初始值不为0时，不显示进度条

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];

初始值设置方式为下下面的方式即可：percentage只能以增长的方式设置

ct.percentage = 0;
ct.percentage += 50;