Implement basic IO (csv, json, images)
Note: only read-write is needed, specialized manipulation and preprocessing should be done in specialized library like [NimData](https://github.com/bluenote10/NimData) and [arraymancer-vision](https://github.com/edubart/arraymancer-vision)

- [x] CSV
- [ ] JSON
- [x] Images (jpeg, png, static gif)