Fixes for windows (#45)

* init Net system on Windows

* propagate DNS error

* Add zlib 1.2.11 sources

* link zlib statically for windows

* remove not implemented function declaration

* fix connect on Windows

ixwebsocket/IXNetSystem.h

@@ -23,3 +23,9 @@
 # include <sys/time.h>
 # include <unistd.h>
 #endif
+
+namespace ix
+{
+    bool initNetSystem();
+    bool uninitNetSystem();
+}