Add generating from archive option, fix exceptions, caused by multiline content in rpm spec files, remove shebangs, fix missing provides_extra field, fix username empty string, add maintainer option, add --local and --localfile in show subcommand, make name attribute optional if --local or --localfile field is provided

Add generating from archive option, fix exceptions, caused by multiline content in rpm spec files, remove shebangs, fix missing provides_extra field, fix username empty string, add maintainer option, add --local and --localfile in show subcommand, make name attribute optional if --local or --localfile field is provided #144