[m-rev.] for review: fix style of integer.m

[Julien Fischer]

On Wed, 21 Oct 2015, Zoltan Somogyi wrote:

> Besides updating if-then-else syntax, this diff also replaces
> a couple of ancient uses of DCGs, turns semidet functions into predicates,
> and improves documentation. I am looking mainly for a review
> of the latter.

That looks fine.

Julien.