* mi-main.c (captured_mi_execute_command): Add uiout parameter.

    * mi-main.c (captured_mi_execute_command): Add uiout parameter.
        "data" is now a structure which is used to pass data to/from this
        function to mi_execute_command.
        Modify function to comply with requirements from catch_exceptions.
        Store real return result and command's return result in data.
        (mi_execute_command): Use catch_exceptions.
        Use enum to handle actions to be performed instead of overloading
        catch_errors return result and the mi return result.