Improve peg rules for names/separator

Now rules are locked to english language:

```
NAME
  = first:[$_a-zA-Z] rest:[$_a-zA-Z0-9]* {
    return first + rest.join('');
  }

NAME_EDGE
  = ![$_a-zA-Z0-9]
```

AFAIK, javascript variables/properties/functions names are not limited to english.

This issue is not critical, because should not happen in real life. But it would be nice to better follow js syntax specifications.
