added support for unix domain sockets
added support for unix domain sockets

If a host name starts with a slash, it is assumed to be a unix domain
socket path.  The port is ignored.  This code is disabled on WIN32,
until someone tests it.

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