Add basic legality checking to KeySAVe, or at least some of the formatters: - [ ] Refactor PKHeX's legality checking into a library: [PkCJ](https://github.com/Cu3PO42/PkCJ) - [ ] Build a JS wrapper around it - [ ] Integrate it into at least the pretty formatter - [ ] Adapt license of distribution and make other required changes to be GPL-compliant
