improvements for handling of save files

src/de/deadlocker8/budgetmaster/logic/Settings.java

...dlocker8/budgetmaster/logic/report/ReportPreferences.java

src/de/deadlocker8/budgetmaster/logic/tag/TagMatch.java

...de/deadlocker8/budgetmaster/logic/utils/SaveFileType.java

...adlocker8/budgetmasterserver/logic/database/Database.java

...dgetmasterserver/logic/database/DatabaseImportExport.java