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.
It would be better to have rejectect / accepted slots, instead of having slots being named after the buttons firing them up. If later Cmd+w is handled ( or other widgets or keys ), it will be weird to connect it to a _on_abort_clicked slot.