Resolved: Hex stuff

[tcharding]

The current hex stuff I've done is pretty wild and is all entangled. I imagine it is going to be a nightmare to be able to ack things.

To help showcase everything I put all the patches on rust-bitcoin/hex-conservative#64 and then did #2473 to prove that it all works.

I'm open to any suggestions that will make the review/merge process easier. FTR the only PR that I think is contentious is the backwards stuff in rust-bitcoin/hex-conservative#67

I can't actually remember right at this minute how I got to thinking that we need a new release of hex for the next rust-bitcoin release, I'll post that if/when I remember or find the rust-bitcoin work that requires it.

We can't do #2474 without fixing hex because of bitcoin::string. So unless we are willing to release units with just the amounts module then the rust-bitcoin release is blocked on all this hex stuff.

[apoelstra]

I think your individual changes are fairly clearly motivated. Thanks for building a tree of PRs like this but I think I'm content to review the non-draft ones (currently #67 and #71) as they come undrafted. Though probably I will take a look at #69 to understand the direction you're taking with the reversed-string stuff.

[tcharding]

Awesome, thanks.