- implement ThreadedFanOut version with return channel
- add test for ThreadedFanOut with return channel

- add all networks triggered from the same node to the same TriggerFanOut
- put all feeding nodes in a TriggerFanOut into the same TransferGroup

- added some class documentation

- some more code cleaning

changed the internal thread implementation to boost::thread and make use of the interruption points to properly terminate the application

- fixed copying only the first element in some situations

partial fix for problems due to moving to new ControlSystemAdapter structure: allocate and use the buffer from the NDRegisterAccessor
tests still do not pass

Adapation to the unified versions of ControlSystemAdapter and DeviceAccess.

Status: Library compiles, tests do not yet compile.

- extended the trigger tests
- removed some debug output

Use the threaded version of the FanOut if a pushing feeder is distributed to multiple consumers, so all consumers receive updates immediately.

- fixed a bug in the FanOut which did not wait for the trigger (since ProcessScalar::receive() does not wait)
- fixed a bug in Application::feedDeviceRegisterToControlSystem() not handling the last arugment (trigger) properly
- improved the output produced with VariableNetwork::dump()

start the synchronisation thread of the FanOut to "convert" a poll-type feeder into a pushing feeder by putting in an external trigger.

Intermediate commit before the weekend: added options to add an external trigger to a network to handle poll and push properly. Currently it does not work properly.

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