ios frontend: sounds and music have their own class now (with caching\!) instead of being spread here and there (exploiting class methods like a true oop pro)

display a message when network is down or server is not reachable, nemo also made the page refresh at display time

many many netclient/frondent changes (just the beginning though): * better separation of concerns * trying to reduce segfaulst due to netclient being deconstructed while still in use * no extra popup for quit reason anymore * errors/warnings will be displayed in chat instead of popups in most cases * NOTE: auto-kick for ignored players is currently _disabled_ will fix that soon