modify zkbind test cases.
Fix bug ZK-1739: treenodes disappearing on frequent updates
http://tracker.zkoss.org/browse/ZK-1739
Bug fixed B65-ZK-1735: Tree overlaps parent container, after update
http://tracker.zkoss.org/browse/ZK-1735
Merge pull request #22 from paowang/master

Fix URL path issue of zkbind test case.
Merge branch 'B65-ZK-1735' of git://github.com/huangnoah/zk