Proposal: Add "fma" to the RealFloat class

[Yitzchak Gale]

Levent Erkok wrote:
>> ...I think this proposal needs to be shelved for the time being.

I wrote:
> Nevertheless, I vote for doing it now.

Edward Kmett wrote:
> As this proposal has been withdrawn, the point is more or less
> moot for now.

OK, let me make myself more clear.

I hereby propose the exact same proposal that Levant originally
proposed in this thread and then withdrew, with the caveat that
the scope of the proposal is explicitly orthogonal to any large
scale change to the way we do floating point.

Discussion period: 2 weeks, minus time spent so far in this
thread since Levant's original proposal.

Thanks,
Yitz