Added default constructors; [for client] added code to throw an exception if socket creation was unsuccessful

includes/server.hpp

@@ -20,6 +20,8 @@ private:
 	}
 
 public:
+	Server() {}
+
 	Server(int ip_ver, char protocol, int port) {
 		/* Error checking */
 		if (ip_ver != 4 && ip_ver != 6) {