* Special Characters in Image File Name
Fix#2415. Fix#1470. If path name of image contains anything other than ASCII, or if it contains # or space or probably other exceptions, PhpSpreadsheet creates a file that Excel cannot, for whatever reason, read (it is valid xml). When adding an image to a spreadsheet, Excel does not retain the original path name; PhpSpreadsheet does, but probably shouldn't. It is changed to save the image file in the zip as the MD5 hash of the original path name. This produces a file that Excel can read. In addition, it ensures that, if the image is used in multiple places, it is saved in the Excel file only once.
Because this error becomes evident only when opening the file in Excel, it is difficult to write a test case. I have instead duplicated sample Basic/05... using image files whose names match the reported error conditions.
* Scrutinizer Minor Error
Remove some newly dead code.
oleibman