Merge branch 'v2_7_0'

.../de/deadlocker8/budgetmaster/charts/ChartDisplayType.java

...va/de/deadlocker8/budgetmaster/charts/ChartGroupType.java

...java/de/deadlocker8/budgetmaster/charts/ChartService.java

...ava/de/deadlocker8/budgetmaster/charts/ChartSettings.java

...ava/de/deadlocker8/budgetmaster/charts/DefaultCharts.java

.../deadlocker8/budgetmaster/controller/AboutController.java

.../de/deadlocker8/budgetmaster/database/DatabaseParser.java

.../deadlocker8/budgetmaster/database/DatabaseParser_v7.java

...de/deadlocker8/budgetmaster/database/DatabaseService.java

...e/deadlocker8/budgetmaster/database/InternalDatabase.java

...adlocker8/budgetmaster/database/model/BackupDatabase.java

...e/deadlocker8/budgetmaster/database/model/BackupInfo.java

.../deadlocker8/budgetmaster/database/model/Upgradeable.java

...dgetmaster/database/model/converter/AccountConverter.java

...getmaster/database/model/converter/CategoryConverter.java

...budgetmaster/database/model/converter/ChartConverter.java

.../budgetmaster/database/model/converter/IconConverter.java

...getmaster/database/model/converter/TemplateConverter.java

...ker8/budgetmaster/database/model/v4/BackupAccount_v4.java

...er8/budgetmaster/database/model/v4/BackupCategory_v4.java