Make arguments to range consistent across examples

When you're showing how to fix the `println` by using `.to_str()`, your
arguments to `range` have inexplicably changed from `(0, 100)` to `(1,
100)`. Then in your first `format!` example, the arguments are `(1, 4)`

I made all these be (1, 100); I could also see these being fixed by
being changed to (0, 100) and then changing them to (1, 101) when you
change 100 to 101 and talk about it.
Merge pull request #61 from carols10cents/range_args

Make arguments to range consistent across examples