message: Fixed links in tutorial.
diff: -* Previous tutorial step - [Step 1 - Lexing](https://github.com/SAP/chevrotain/blob/master/docs/01_Tutorial/step1_lexing.md)
  +* Previous tutorial step - [Step 1 - Lexing](./step1_lexing.md)
  # Tutorial Step 2 - Building a Parser.
  