Accept a new connection on self

Require the socket to be first bound and listening for connections

Property definitions

socket $ NativeSocket :: accept
	# Accept a new connection on `self`
	#
	# Require the socket to be first bound and listening for connections
	fun accept: nullable SocketAcceptResult
	do
		var addrIn = new NativeSocketAddrIn
		var s = native_accept(addrIn)
		if s.address_is_null then return null
		return new SocketAcceptResult(s, addrIn)
	end
lib/socket/socket_c.nit:220,2--229,4