Fix bug ZK-1524: use caption in window will cause hflex="min" doesn't work
http://tracker.zkoss.org/browse/ZK-1524
Fix bug ZK-1574: window vflex="min" calculate wrong height in tablet
http://tracker.zkoss.org/browse/ZK-1574
Merge remote-tracking branch 'VincentJian/B65-ZK-1524'