Bug ZK-2267: Popup is only sometimes "visible" when it is opened
add testcase in config.properties
Merge branch '6.5' of https://github.com/zkoss/zk into 6.5
add testcase
* fixed jsdoc issue
* add release date for 6.5.6
Merge branch '6.5' of github.com:zkoss/zk into 6.5
release 6.5.6
upgrade version to 6.5.7
Bug ZK-2296: After selecting an item, combobox's dropdown will scroll to right automatically
Bug ZK-2294: Combobox popup scroll back to top when navigating by keyboard
Bug ZK-2295: Move tree item causes selection status lost
Bug ZK-2285: Problem with keyboard selection in listbox with select mold [IE]
refix ZK-2294 and for those test cases, B60-ZK-1202.zul, B65-ZK-2296-1.zul, B65-ZK-2193.zul, and F70-ZK-1924.zul

Conflicts:

	zk/src/archive/web/js/zk/dom.js
bug fixed for test case B36-2935398.zul and B65-ZK-2019.zul

Conflicts:

	zk/src/archive/web/js/zk/au.js
	zktest/war.libs.all
Refine the fixed of ZK-2296 and fix for ZK-2328.
Bug ZK-2331: Combobox drop-down sometimes not open on top of input element if the browser space is not enough