Add Machine::set_user_input(&mut self, input: String) and get_user_output() -> String. Make read_term_from_user_input() handle Stream::Byte.

src/machine/machine_state.rs

@@ -495,6 +495,10 @@ impl MachineState {
             }
         }
 
+        if let Stream::Byte(_) = stream {
+            return self.read_term(stream, indices)
+        }
+
         unreachable!("Stream must be a Stream::Readline(_)")
     }