Replace seahash with rapidhash

[hoxxep]

Hi!

Maintainer of rapidhash here, and I saw that you were using seahash in trunk.

I believe rapidhash comprehensively beats seahash in quality and speed on all platforms, especially for long string/byte hashing. It's fully portable and doesn't rely on any hardware acceleration.

I couldn't find any benchmarks in the repo, but hopefully this improves project build times for users?

Very happy to answer any questions. Cheers!

[ctron]

TBH, I am not sure if this is a pressing concern. And without any benchmarks, it feels hard to justify.

[hoxxep]

Fair point! I wrote a quick script to run the dist step for all examples, and I see it takes mere milliseconds to complete as the files max out at a few hundred kilobytes. I can agree it's perhaps not worth justifying here.

If a user is hashing many megabytes worth of files then the difference would be more notable, as rapidhash should be 5-10x faster on most platforms. Are larger builds or image assets occasionally hashed by users in the trunk dist step, in the same way they might be by static site generators?