Update to cuda 11

• Update to cuda 11

OpenCL PoH

v0.19.3

Check seed fread

Double speed ed25519 verify and chacha removed

Remove chacha implementation

Archivers are on hold for now.

Fail sig verify if public key is small order check

In the cuda sig verify, ensure that the public key is not small order.

SIMD PoH

Add an ISPC implementation of sha256-based PoH with builds for sse, avx2, avx-512.

Signature malleability checks

In signature verify, check for reduced Signature.s and unpack Signature.R as group element and check torsional components.

CUDA 10.2 support

v0.18.0

Add cuda 10.2 support

OpenCL Support

Add OpenCL support for ed25519 signature verify.

Fix extra cudaMalloc in the sign path

In the sign_many path, the value for saving the size of the out buffer was not correct, so a cudaFree/cudaMalloc would occur each kernel launch. This release fixes this behavior.

Fix verify performance

v0.16.0 regressed verify performance, this release is to restore that.