upgrade build version to 3.0.2 & 3.9.3
rename a method to follow POI naming convention.
Correct fix for ZSS-633. Cannot use customWidth flag to decide importing column width because hidden column's customWidth is also true. Previous fix doesn't pass the test case: hidden column has default width.
Merge branch 'origin/3.0'
add comments on AbstractExcelImporter.
Conflicts:
	build.setting
	zss/src/org/zkoss/zss/ui/Spreadsheet.java