Namespaces and composer
Merge branch 'master' into namespace
[TASK] Refactored GroupHeader to bereusable by other TransactionTypes
[TASK] Refactorings for more generic filebuilding
[TASK] Support for more SEPA cases

Changed to different pain implementation as these seem to be the latest
supported by german Institutions

Added Classstructure as DIA-File
More test to check for correct calculation of control sums and transactions

Removed unused pain files

Facade to direct debit for easy access to the structure