add tiny cross-platform TCP socket library from https://github.com/DFHack/clsocket

(todo: hook-up to Bullet cmake/premake build systems, and implement TCP alternative for UDP server)

test/clsocket/EchoServer.cpp

@@ -0,0 +1,44 @@
+
+#include "PassiveSocket.h"       // Include header for active socket object definition
+
+#define MAX_PACKET 4096 
+
+int main(int argc, char **argv)
+{
+    CPassiveSocket socket;
+    CActiveSocket *pClient = NULL;
+
+    //--------------------------------------------------------------------------
+    // Initialize our socket object 
+    //--------------------------------------------------------------------------
+    socket.Initialize();
+
+    socket.Listen("127.0.0.1", 6789);
+
+    while (true)
+    {
+        if ((pClient = socket.Accept()) != NULL)
+        {
+            //----------------------------------------------------------------------
+            // Receive request from the client.
+            //----------------------------------------------------------------------
+            if (pClient->Receive(MAX_PACKET))
+            {
+                //------------------------------------------------------------------
+                // Send response to client and close connection to the client.
+                //------------------------------------------------------------------
+                pClient->Send( pClient->GetData(), pClient->GetBytesReceived() );
+                pClient->Close();
+            }
+
+            delete pClient;
+        }
+    }
+
+    //-----------------------------------------------------------------------------
+    // Receive request from the client.
+    //-----------------------------------------------------------------------------
+    socket.Close();
+
+    return 1;
+}