Added the new cache file to implementation of ticket #354
Added assignment operators to implementation of ticket #354
Added the (temporary) UTF8-Parser to implementation of ticket #354
Included Igor binary waves to implementation of ticket #354
Included arbitrary text data files to implementation of ticket #354
Included XLSX SpreadSheets to implementation of ticket #354
Included XLS SpreadSheets to implementation of ticket #354
Included OpenDocumentSpreadSheets to implementation of ticket #354
Included JCAMP-DX to implementation of ticket #354
Created branch for ticket #354 "Add headers to the cache and the NDAT files"