26902 Initial code review

Created a branch from the very first commit to be able to review the whole code written so far.
This does not mean that a merge should be done after the review is done, this is a "dummy" pull request.
I don't feel this the right way to do this. A Qt logging handler should be registered when Qt is available, which would emit a signal. The engine should connect a slot to it, which would pop up a QMessageBox, or display the message anywhere it fancies. This method should only ensure that any exception goes through the logger, which I think is its main goal.