Major Refactors

[erhant]

• [x] Group all testing stuff under the tests folder. Only the src and tests should be at the top level, along with the circomkit.json.
• [ ] Resolves #47 : Will use commander
• [ ] Refactor Circomkit functions for better modularism & readability
• [ ] Move SnarkJS to peer-dependency. (TODO: will check with others first)
• [ ] Resolves #67 : Add circuit-specific config overrides
• [ ] Fixes #80
• [ ] Resolves #68
• [x] Use a better build tool than TSC, resolves #81 | using pkgroll
• [ ] Add examples folder with some examples, perhaps #78 , with GoRapidsnark, and with several JS-based test suites.