* rework backend to instantiate key at initialization
* add groth16 convertes for solidity
* prover taks num samples on construction
* add zkey file
* rework helpers
* rename types
* update tests
* reworked test helpers
* rename types
* rework test
* test all slots artifacts
* bump to latest version
* wire in circom backend
* should contain leafs
* adding circom compad and circuits deps
* update windows build
* fix windows build
* improve test names
* move proving defaults to codextypes
* remove unnedded inmports and move defaults to codextypes
* capture error code on backend failure
Mark Spanbroek
Dmitriy Ryajov