add a manual test case for ZSS-589
fix ZSS-589 Hidden rows are still displayed in IE
add manual test case for zss-617
fix ZSS-617 After spreadsheet loads a book, a mask is blocking the sheet
add performance testcase
add test file for zss-589
ZSS-612: Don't allow sort book dialog in ZSS app
Update release-note for ZSS-612
tune performance test
Merge commit '784ab0b9a05e86d404b36ecc5e3ce02a33417bfd' into 3.5
Merge branch '3.0' for zss-617

importer should import custom width flag.
Conflicts:
	zss/src/org/zkoss/zss/ui/Spreadsheet.java
Merge branch 'origin/3.0' for zss-612, performance test

Conflicts:
	zkdoc/release-note
add manual test case for zss-616
fix ZSS-616 Selection box is displayed at wrong position.
wait until sheet css is ready, then process wrap. Or calculation of row height will be wrong.
update release note for 3 issues by merging 3.0
Merge branch '3.0' for ZSS-616

Conflicts:
	zkdoc/release-note
* test case for ZSS-595 & ZSS-592
fix ZSS-592 & ZSS-595 (handle insert/delete cover freeze pane)
fix ZSS-608 and its test case
update release-note for ZSS-608, ZSS-595, ZSS-592