We have a visitor now for generating
 - the XML
 - the Module's dot graph
 - the textual dump of the VariableNetwork
 - the dot graph of the VariableNetwork

It inherits two functions from its two base classes. Explicitly use the
one from ApplicationBase.

use a different work around for the thread_local problem: moving the code using the thread_local specifier to the cc file also solved the problem and does not require a complicated work around using a map...

refactored a type if-then-else monster into a for_each loop and exlcuded a pure cout function from the converage report

- clarified some comments

fixed connectTo() so it now uses the dynamic/virtual model and thus obeys e.g. eliminated hierarchies etc.

Renamed Application::testableModeThreadName() into Application::threadName(), since this will be used for other purposes as well.

Instead of making the DeviceModule return the same VariableNetworkNode for the same register, an optimisation step before realising the connections (but after all connections have been defined) is performed. In this step, all networks sharing the same (device-type) feeder will be merged. This is more flexible and avoids problems with (potentially different) triggers etc.

detect stalled tests and print a list of variables which contain data not processed by the application

- prevent spamming of some messages in debug testable mode

- allow setting the "eliminateHierarchy" flag in the constructor of a module

This is an interface change which was done in an incompatible way!

made the instance of the Application::testableMode_mutex static, since otherwise the unique_locks returned are no longer valid in any but the first instance of the application (which affects tests)

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 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