added "about" section in help dialog (containing license, feedback and maintainer info)
added "about" section in help dialog (containing license, feedback and maintainer info)

dex2000/overpass-turbo,elbakai/overpass-turbo,elbakai/overpass-turbo,Secretmapper/overpass-turbo,Secretmapper/overpass-turbo,dex2000/overpass-turbo