Implement DAV support (#237)

Author: cpq

Makefile

@@ -31,7 +31,8 @@ difftest:
 w:
 	wine cl test/unit_test.c fossa.c /Zi /nologo /MD advapi32.lib \
 	-DNS_ENABLE_COAP -DNS_ENABLE_THREADS -DNS_INTERNAL= \
-	-DNS_ENABLE_MQTT_BROKER -DNS_ENABLE_DNS_SERVER
+	-DNS_ENABLE_MQTT_BROKER -DNS_ENABLE_DNS_SERVER /Fetest/unit_test.exe
+	(cd test && wine unit_test.exe)
 
 update-frozen:
 	git subtree pull --prefix deps/frozen https://github.com/cesanta/frozen master --squash