#598 - added backup model for tags (avoid circular reference on json export)

...dlocker8/budgetmaster/database/model/v4/BackupTag_v4.java

...er8/budgetmaster/database/model/v4/BackupTemplate_v4.java

.../budgetmaster/database/model/v4/BackupTransaction_v4.java

...er8/budgetmaster/database/model/v5/BackupTemplate_v5.java

.../budgetmaster/database/model/v5/BackupTransaction_v5.java

...etmaster/database/model/v5/converter/TagConverter_v5.java

...ter/database/model/v5/converter/TemplateConverter_v5.java

.../database/model/v5/converter/TransactionConverter_v5.java

...er8/budgetmaster/unit/database/DatabaseParser_v4Test.java

...er8/budgetmaster/unit/database/DatabaseParser_v5Test.java