Fixed signed comparison warnings in ztproxy when compiling under Windows

src/ZT1Service.cpp

@@ -89,7 +89,7 @@ ZeroTier::VirtualTap *getTapByAddr(ZeroTier::InetAddress *addr)
 	for (size_t i=0; i<ZeroTier::vtaps.size(); i++) {
 		s = (ZeroTier::VirtualTap*)ZeroTier::vtaps[i];
 		// check address schemes
-		for (int j=0; j<s->_ips.size(); j++) {
+		for (size_t j=0; j<s->_ips.size(); j++) {
 			if ((s->_ips[j].isV4() && addr->isV4()) || (s->_ips[j].isV6() && addr->isV6())) {
 				//DEBUG_EXTRA("looking at tap %s, <addr=%s> --- for <%s>", s->_dev.c_str(), s->_ips[j].toString(ipbuf), addr->toIpString(ipbuf2));
 				if (s->_ips[j].isEqualPrefix(addr)