Added description field to the variables. It is currently ignored and will be added to the XML file in a next step.

- extended the trigger tests
- removed some debug output

Split the SCALAR_ACCESSOR macro into SCALAR_OUTPUT and SCALAR_INPUT to prevent output accessors to be created in poll mode (which makes no sense). Since some tests were using this, now instead a DeviceAccessor in poll mode is used for these tests.

removed a function declaration which was not implemented and cannot be implemented right now (missing feature in the CSA)

improved structure of network creation and added a FanOut to distribute values to multiple consumers

This is a first mock implementation with very limited functionality. The idea is based on discussions during the OPC-UA control system adapter kickoff meeting and subsequent personal discussions.