[m-rev.] for review: make many integer casts into builtins

[Julien Fischer]

Hi Zoltan,

On Fri, 25 May 2018, Zoltan Somogyi wrote:

> On Thu, 24 May 2018 15:00:09 +0200 (CEST), "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
>> OK, will do.
>
> Attached is the first module I worked on. Unless someone
> objects in the next 24 hours or so, I will use it as the template
> for the others.

No objections, but a couple of comments.

s/won't/will not/ in a spot.

I think the function that return the limits of the type (min_int64 and
max_int64) should live in their own section and not be grouped together
with the comparison predicates.

Julien.