Lisaac prototype interface

Section Header
+ name :=STD_INPUT_OUTPUT;
- comment :="To have the useful `io'";
Section Inherit
- parent_input_stream:INPUT_STREAM :=
- parent_output_stream:OUTPUT_STREAM :=
Section Public
- is_connected:BOOLEAN :=
- make <-
- read_character <-
- unread_character <-
- push_back_flag:BOOLEAN <-
- last_character:CHARACTER <-
- put_character c:CHARACTER <-
- end_of_input:BOOLEAN <-
- read_line_in str:STRING <-