ZSS-397:
 * clear drawing anchor when deleting picture.
 * clear drawing part when no anchors.
 * change picture delete event's data to ID only.
ZSS-397: modify issue ID in comments
* ZSS-358: add axis ID into chart element (fixed in POI)
* modify test case
* ZSS-358: change chart delete event's data to ID only.
* update release note
Merge branch 'ZSS-358' into 3.0

Conflicts:
	zss/src/org/zkoss/zss/model/sys/impl/BookHelper.java