moved VariableNetworkNode member to AccessorBase class, so the network node information can be accessed also when having only the pointer to the base class

allow specifying the array length for direct connections between device and control system (as the type is already defined in this case)

- fixed copying only the first element in some situations

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

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

Introduced the DeviceModule class which provides an interface to obtain VariableNetworkNodes for device registers

- performed some code cleaning and refactoring
- store all nodes in a VariableNetwork in a single list, to allow deciding later if a node is feeding or consuming

This commit is an intermediate commit and has known bugs. Almost all tests are failing and the demoApp is not running. Debugging will be done in a next step.

introduced an operator>> and operator<< syntax to connect network nodes. to realise this, the VariableNetworkNode class has been changed into a pimpl pattern.

Allow to make connections directly based on VariableNetworkNodes. This is a first step, more changes have to be made in this direction.

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

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.

Remove the restriction which prevented connecting nodes of the same direction. This was an artificial restriction, since later checks make sure that the network has exactly one feeder.

- 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()