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/IXSocketConnect.cpp

@@ -57,10 +57,10 @@ namespace ix
         SocketConnect::configure(fd);
 
         if (::connect(fd, address->ai_addr, address->ai_addrlen) == -1
-            && errno != EINPROGRESS)
+            && errno != EINPROGRESS && errno != 0)
         {
-            closeSocket(fd);
             errMsg = strerror(errno);
+            closeSocket(fd);
             return -1;
         }