Circom external inputs (#91)

* circom: add external_inputs

* adapt new external_inputs interface to the FoldingScheme trait and Nova impl

* adapt examples to new FCircuit external_inputs interface

* add state_len & external_inputs_len params to CircomFCircuit

* add examples/circom_full_flow.rs

* merge the params initializer functions, clippy

* circom: move r1cs reading to FCircuit::new instead of each step

* CI/examples: add circom so it can run the circom_full_flow example

.github/workflows/ci.yml

@@ -79,10 +79,18 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
+      - name: Download Circom
+        run: |
+          mkdir -p $HOME/bin
+          curl -sSfL https://github.com/iden3/circom/releases/download/v2.1.6/circom-linux-amd64 -o $HOME/bin/circom
+          chmod +x $HOME/bin/circom
+          echo "$HOME/bin" >> $GITHUB_PATH
       - name: Download solc
         run: |
           curl -sSfL https://github.com/ethereum/solidity/releases/download/v0.8.4/solc-static-linux -o /usr/local/bin/solc
           chmod +x /usr/local/bin/solc
+      - name: Execute compile.sh to generate .r1cs and .wasm from .circom
+        run: bash ./folding-schemes/src/frontend/circom/test_folder/compile.sh
       - name: Run examples tests
         run: cargo test --examples
       - name: Run examples