Fixed bugs and fixes

[GermanAizek]

@erikh, @laduke, hi. Review code, point to flaws and feedback me. Commit title: Fixed bug with aqm queues, check nullref queueAtFrontOfList before use, delete NSM connection before return

[erikh]

probably best to have @adamierymenko poke at this one

[joseph-henry]

Thank you for this effort, however further development on the AQM topic will be exclusively on the rust branch.