list: use mpd_send_command2()
list: use mpd_send_command2()

The new function mpd_send_command2() simplifies the flag updates in
the command list functions, and fixes a bug.

yusiwen/libmpdclient,jagleeso/libmpdclient,cmende/libmpdclient,yusiwen/libmpdclient,psych0tik/libmpdclient2,sl0th/libmpdclient,jwise/libmpdclient,jwise/libmpdclient,jwise/libmpdclient,psych0tik/libmpdclient2,OpenInkpot-archive/iplinux-libmpdclient,yusiwen/libmpdclient,sl0th/libmpdclient,cmende/libmpdclient,cmende/libmpdclient,sl0th/libmpdclient,OpenInkpot-archive/iplinux-libmpdclient,jagleeso/libmpdclient,jagleeso/libmpdclient