refactor ArrayAccessor and ScalarAccessor: split off common code and put into common base class InversionOfControlAccessor

Fixed some more problems with the move sematics of EntityOwner/Module. Re-registration at the owner was missing and some things were done in the wrong place. Also the move assignment is now back again.

put the move constructor and move assignment-operator into the EntitiOwner base-class and inherit them

introduced a ModuleGroup (grouping ApplicationModules and other ModuleGroups) and enforced a proper hierarchy of modules to exclude that an ApplicationModule can own (directly or indirectly) another ApplicationModule

update for interface change in DeviceAccess: TransferElement::write() has now the version number as an argument

allow determining a fully qualified name for application variables (i.e. including qualified name of owning module)

made Module::connectTo() compile-time polymorphic, to allow special modules with operator() returning a different type.

Fixed several bugs affecting poll-type variables being read by a poll-type application variable and distributed to push-type variables via a ConsumingFanOut.

Changed Module::readAll() to read all push-type variables first, to make sure that poll-type variables are up-to-date upon return

This reverts commit 7287c4b4.

revert last commit, cascading ApplicationModules should be avoided instead (and should be prevented in future)

Cache accessors obtained through TestFacility::getScalar() and TestFacility::getArray() by the application test code, to avoid the loss of the current value if a decorated accessor is obtained again.

also make sure for DeviceModules to always return the same sub-module with the [] operator when passing the same sub-module name

fixed not returning the same submodule on a second call of the ControlSystemModule::operator[] with the same module name

don't crash the application if Profiler::startMeasurement() is called while the measurement is already running, instead just ignore the second call

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

moved the xml generator main function into a new header file, to avoid defining main() multiple times by mistake.

moved group read/write and []/() oprerators from the VariableGroup class into the Module class, to make the functionality also available in ApplicationModules

added function to obtain the qualified name of the variable, including the hierarchy path. not yet used.

- use this return type in testable mode to detect when a queue overflow happened (testable mode counter should not increase in that case)

When optimising the connections (i.e. merging networks), the trigger receivers for triggered networks are now removed from the trigger network. This was previously leading to crashes.

renamed VariableNetwork::addTriggerReceiver() into VariableNetwork::addNodeToTrigger() for better clarity