Fix command-line tty-device|config parsing

Allow user to add options on both sides of the provided config argument.

For example:

 $ tio -b 9600 am64-evm -e

Before, tio only allowed adding arguments after the config argument.

Implemented as simple as possible by introducing two stage option parsing.

src/configfile.h

@@ -38,6 +38,6 @@ struct config_t
 	char *map;
 };
 
-void config_file_print();
-void config_file_parse(const int argc, char *argv[]);
+void config_file_print(void);
+void config_file_parse(void);
 void config_exit(void);