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

test/IXTest.h

@@ -52,6 +52,5 @@ namespace ix
 
     void log(const std::string& msg);
 
-    bool computeFreePorts(int count);
     int getFreePort();
 }