added preliminary support for tags to application variables which can be searched for and used to generate virtual modules

- delete the copying operator=

made the instance of the Application::testableMode_mutex static, since otherwise the unique_locks returned are no longer valid in any but the first instance of the application (which affects tests)

- updated the tests for the testable mode and test the TestFacility class there as well

fixed race condition in testable mode: now stepApplication() will use a semaphore counter to ensure that all processing is done

implement the "testable mode" in which the application can be paused and resumed by the test routine

Added a TestDecoratorRegisterAccessor which is optionally put around accessors to facilitate test of applications. This TestDecoratorRegisterAccessor does not yet do anything, functionality will be added in the next commits.

fixed replacing Array and ScalarAccessors, which was broken after moving to the NDRegisterAccessorBridge-based accessors

fixed poll-type inputs using no longer non-blocking read after the switch to the NDRegisterAccessorBridge-based accessors

Rebased the ScalarAccessor and ArrayAccessor classes onto the mtca4u::NDRegisterAccessorBridge class.
Known problems present: code compiles but tests do not run

Changed the FeedingFanOut so that it does not extract the meta-data (name, shape etc.) from the first slave but expects it in the constructor. This is necessary since the meta-data is already given by the application.

fixed variable networks with external trigger not being put into the same TriggerFanOut (which is required since they should be in the same TransferGroup)

- 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