Decimal numbers operations

[XVilka]

Decimal arithmetic is very popular among financial computations, to prevent rounding errors.
And with the creating Business Applications Working Group it makes sense to make these libraries more mainstream (i.e. make some code a part of rust-num organization):

• crate: decimal, repository
• crate: rust-decimal, repository
• crate: bigdecimal, repository

See also alkis/decimal#55, paupino/rust-decimal#197, akubera/bigdecimal-rs#60

[cuviper]

For some history, see also #8 and all the related issues linked therein, like PR #224.

it makes sense to make these libraries more mainstream (i.e. make some code a part of rust-num organization)

I'd rather de-emphasize @rust-num as being of particular importance -- we are only two maintainers, and the other person isn't very active here at all. The authorship of "The Rust Project Developers" is only kept for historical reasons, since most of num was extracted from the Rust standard library in the final push for Rust 1.0 stabilization.

I don't want to be in the business of picking winners among crates that I'm not even involved in. Any of those three alternatives have a chance to succeed in this space on their own. If your working group wants to promote one, that's up to you.