Make "Position Direct" default control mode of "SetReference" instead of "Position" control mode?

[traversaro]

From what I understand, the "Position" control mode is the default control mode of "SetReference" block. I think this is far from ideal, as the "Position" could make sense in Simulink context only if the user is aware of the fact that is sending a reference to a trajectory generator, and so does not frequently change the reference value (see

wb-toolbox/toolbox/library/src/SetReferences.cpp

Lines 407 to 426 in 7804a8e

	// Do not update the position reference if it didn't change.
	// This would generate a warning.
	const auto oldReference = pImpl->previousReferenceVocabCmPosition;
	const auto& dofs = robotInterface->getConfiguration().getNumberOfDoFs();
	pImpl->previousReferenceVocabCmPosition.assign(bufferReferences,
	bufferReferences + dofs);
	if (oldReference == pImpl->previousReferenceVocabCmPosition) {
	ok = true;
	break;
	}
	// Get the interface
	IPositionControl* interface = nullptr;
	if (!robotInterface->getInterface(interface) || !interface) {
	bfError << "Failed to get IPositionControl interface.";
	return false;
	}
	// Convert from rad to deg
	SetReferences::impl::rad2deg(bufferReferences, signalWidth, pImpl->degBufferReferences);
	// Set the references
	ok = interface->positionMove(pImpl->degBufferReferences.data());

).

At the minimum, we should change the default control mode to something less "strange", for example position direct.