Fixed #66: equal numbers issue different hashes

[spektom]

The idea is to use decQuadReduce() function that eliminates insignificant zeroes from the number before hashing.

[jonathanstrong]

hey - just looking at this. thank you for submitting the pull request.

I did have one question, I'm not familiar with what trim/decNumberTrim does. I realize you switched to reduce, which makes sense, but is there an independent function of trim that we possibly want to offer for its own reasons?

[spektom]

@jonathanstrong hey, sorry I don't follow. Are you asking whether trim should be part of Rust API?

[jonathanstrong]

potentially? the C code has a comment describing decNumberTrim as "remove insignificant zeros", while the comment for decNumberReduce is "remove trailing zeros". I don't understand how these are different in terms of functionality, and would like to for the purposes of assessing whether the Rust api should also provide a trim method on d128.

[spektom]

Frankly, I don't know. decNumberTrim is a utility function as it's called internally, I'm not sure it should be part of the API. Anyway, I don't think this decision should be made as part of this PR.

[spektom]

@jonathanstrong is there a concern regarding usage of decNumberReduce()?