Enable Http/1.1 persistence connection

This enables reusing existing TCP connection instead of opening a new connection
for every request

src/base/http/connection.cpp

@@ -101,12 +101,10 @@ void Connection::read()
                 if (acceptsGzipEncoding(result.request.headers["accept-encoding"]))
                     resp.headers[HEADER_CONTENT_ENCODING] = "gzip";
 
-                resp.headers[HEADER_CONNECTION] = "close";
+                resp.headers[HEADER_CONNECTION] = "keep-alive";
 
                 sendResponse(resp);
                 m_receivedData = m_receivedData.mid(result.frameSize);
-
-                m_socket->close();
             }
             break;