mod(::fmpq, ::Int) inconsistent with Julia

[wbhart]

This one is very unfortunate. The Julia folks seem to have decided that mod should not reduce modulo the second argument but should basically give some version of Euclid's remainder function.

julia> mod(2//3, 5)
2//3

julia> mod(QQ(2, 3), 5)
4

I think it is Julia that is incorrect here, not us. I can't imagine anyone wanting that definition.

But what to do about it.

Should we choose another name? Ignore the issue with Julia? Leave things incompatible?