new curves (e.g Ed25519 and Ed448)

[kazu-yamamoto]

@ocheron Is https://github.com/ocheron/hs-tls/tree/newcurves ready for merging?
This conflicts with #298. In my impression, we should merge newcuves (and downgrade-protection) first then tackle #298.

[kazu-yamamoto]

@ocheron @vdukhovni Here is an example of merge plan for downgrade-protection, newcurves and tls13-client-auth: https://github.com/kazu-yamamoto/hs-tls/tree/proj

Maybe the code is redandant but all test cases pass.

[kazu-yamamoto]

Ping @ocheron
Would you tell me the status of newcurves?
If it takes time, I will merge #298 first.

[ocheron]

Would you tell me the status of newcurves?

This is basically my work from 2017 without ECDSA, and rebased on top of TLS13.
Will need to go through PR and review. HEAD is moving fast but rebase is still clean it seems.

[kazu-yamamoto]

OK. I will merge #298 first. newcurves will conflict with the new master.
You can see how to resolve the conflict in https://github.com/kazu-yamamoto/hs-tls/tree/proj though the merge ordering is flipped.