This problem is the same as #1238, which was resolved by #1239.
For that issue, the fix was to check in one place whether
$this->mapCellXfIndex[$xfIndex] was set before using it.
The sample spreadsheet supplied as a description for this
problem had exactly the same problem in 2 other places in the code.
In addition, there were 7 other places in the code where that
particular item was used unchecked. This fix corrects all 9 locations.
The spreadsheet supplied with the problem is used as the basis
for some new tests, which particularly test column dimensions
and styles, the problems involved in this case.
38fab4e632