retain frontend effects setting exiting/leaving settings

Fix some warnings

Stop messages without possible desync on load from save

I didn't want to do this since it seems less clean, but... moving the stats-fix into CheckForWin, since that function is the one sending the damage stats (whyyyy?) therefore it's not sufficient to update stats after calling it, some of the stats won't be transfered to frontend then

Show who is the room admin on join (no tested, also I don't like how it is done via server warnings, but it seems there's no other solution compatible with .17)

skip second CheckForWin if water wasn't raised after first one

fix multi-shot related game ends leading to incomplete stats, fixes issue #372

More Qt-ish code, fix couple warnings.