Multiple listeners support

CPPSERV is now capable of listening on multiple sockets in parallel. This is not that important in itself - there are very few reasons to listen on different TCP sockets for now in most settings, except maybe in case of multi-IP machines, where you don't want to listen on all interfaces (is this sentense too long, or what?). However, another important feature was added as well - that is ability to listen on Unix-domain sockets, which is lot more efficient then TCP for local communication. Preliminary tests have shown 10-15% speed difference.
Unix-domain socket support still needs to be added to ligttpd module though.