Refactor typedarray - #740

Hmm, making these reusable seems to add more code (as of text) to stdlib for something that the related PR can solve with just a couple lines. Not sure if worth it, considering that these things become inlined anyway. Or will there be more Buffer methods that will benefit from it?

This provides more reusable code for Buffer in the future or any other similar class. I know NEAR use some custom byte buffer containers and The Graph so it could be useful for others

I like this. Might make the Buffer class smaller in the node project too.

I suggest documenting each one in the types file too. May I do that?

Ok, let's do it then :) (not sure about the types file as these are internals)

The only problem I see is that libraries could couple themselves to these internal functions. (as node will).

We shouldn't drop support for the functions if they are going to be exported and used in the std node library. As long as these functions are going to stick around, I'm okay with this pull request.

Is there a schedule for reviewing? I don't know if there's something wrong with my pull requests or I can move on and start working on other things.