Cleanup (#27)

* VerificationCircuit --> NIFSVerifierCircuit, for clarity

* InnerCircuit --> StepCircuit

* Rename

* cleanup imports

* additional cleanup in the test

* small cleanup

src/bellperson/r1cs.rs

@@ -2,8 +2,7 @@
 
 #![allow(non_snake_case)]
 
-use super::shape_cs::ShapeCS;
-use super::solver::SatisfyingAssignment;
+use super::{shape_cs::ShapeCS, solver::SatisfyingAssignment};
 use bellperson::{Index, LinearCombination};
 
 use ff::PrimeField;

src/bellperson/shape_cs.rs

@@ -1,7 +1,9 @@
 //! Support for generating R1CS shape using bellperson.
 
-use std::cmp::Ordering;
-use std::collections::{BTreeMap, HashMap};
+use std::{
+  cmp::Ordering,
+  collections::{BTreeMap, HashMap},
+};
 
 use crate::traits::{Group, PrimeField as PF};
 use ff::{Field, PrimeField};