Bump ff & group to 0.13

[huitseeker]

Still testing this, in particular, the rust-gpu-tools import on the cuda / opencl features may have some issues.

Edit: solved by upgrading rust-gpu-tools to 0.7.1 in upstream ec_gpu.

Depends on filecoin-project/bellperson#304
Fixes #171

Edit(4/14): this needs work on the pasta-fil-curves repo.
Edit. (4/15): I'm seeing issues with tree builder tests hanging on opencl. Is this something you're seeing as well @porcuquine ?

Historical (solved) issue:
https://gist.github.com/huitseeker/230caa8cd63e049846f95ac0d8c77fe5

huitseeker@lightning.local➜~/tmp/neptune(bump_ff_group)» cargo tree -p rust-gpu-tools -i                                                                                                                                             [12:48:10]
warning: patch for `blstrs` uses the features mechanism. default-features and features will not take effect because the patch dependency does not support this mechanism
rust-gpu-tools v0.7.0
└── ec-gpu-gen v0.5.2 (https://github.com/filecoin-project/ec-gpu/?branch=upgrade-ff-013#9616bd3c)
    ├── bellperson v0.24.1 (https://github.com/huitseeker/bellperson?branch=update-ff-group#36a75691)
    │   ├── gbench v0.5.4 (/Users/huitseeker/tmp/neptune/gbench)
    │   └── neptune v8.1.1 (/Users/huitseeker/tmp/neptune)
    │       └── gbench v0.5.4 (/Users/huitseeker/tmp/neptune/gbench)
    ├── gbench v0.5.4 (/Users/huitseeker/tmp/neptune/gbench)
    └── neptune v8.1.1 (/Users/huitseeker/tmp/neptune) (*)
    [build-dependencies]
    ├── bellperson v0.24.1 (https://github.com/huitseeker/bellperson?branch=update-ff-group#36a75691) (*)
    └── neptune v8.1.1 (/Users/huitseeker/tmp/neptune) (*)
    ```

[vmx]

The problem was that CudaContexts wasn't Send. I've just released version 0.7.1 which should fix the issue.

[vmx]

Edit(4/14): this needs work on the pasta-fil-curves repo.

The nice thing about this upgrade is that fil_pasta_curves should no longer be needed. Upstream pasta_curves should just work.

[huitseeker]

@vmx Correct. A msiconfig in test flags momentarily made me think there was something missing in ec_gpu. Fixed in 267bf6d.

[huitseeker]

Took a while, but I can now confirm this works on both cuda and opencl:

EC_GPU_FRAMEWORK=opencl cargo test --release  --features "arity2,arity4,arity8,arity11,arity16,arity24,arity36,pasta,opencl,bls" -- --test-threads=1 --nocapture

https://gist.github.com/huitseeker/e79b04794276989604c646d296662d27

EC_GPU_FRAMEWORK=cuda cargo test --release  --features "arity2,arity4,arity8,arity11,arity16,arity24,arity36,pasta,cuda,bls" -- --test-threads=1 --nocapture

https://gist.github.com/huitseeker/98f65366722d5296bcc4037081e41bb9