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.

renamed publishDeviceReadRegister() and publishDeviceWriteRegister() into feedDeviceRegisterToControlSystem() and consumeDeviceRegisterFromControlSystem()

renamed publish() and connectToDevice() into more specific feedToControlSystem()/consumeFromControlSyste() and feedToDevice()/consumeFromDevice()

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

Introduced the VariableNetwork describing the connections of variables/accessors before things get actually instantiated. This is needed to generate an XML file containing the published variables based on that information.

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.

fix for the latest DoocsAdapter: the module name is used as the location name, so the module has been renamed into "MyLocation" to match the DOOCS config file

set required version of DeviceAccess to 00.12, since the build environment variables might have changed

added a variable @PROJECT_NAME@_PREFIX and use it as the required variable to make a nicer output when depending projects find this package

removed @PROJECT_NAME@_LIBRARIES from the required variables since the package might not provide a library

Use FindLibrary() cmake command to properly locate the library, even if the directory is already known. This is needed to get the proper full path reference to the library.

fixed issue with compiler/linker flags being interpreted as lists and thus having semicolons in between