Data loading and handling

[Sophon96]

We need some way to load data formats, such as CSV, Apache Parquet, HDF. There's libraries for these in C++, but I'm not sure how well they integrate. I don't know if there's a ubiquitous data science data library like pandas for C++, which might be preferable to use.

[adamhutchings]

Even if we write our own, I think all functions of this sort that are not directly related to machine learning should go in a top-level folder separate from core/. Any good name ideas or thoughts?

[Sophon96]

I think we shouldn't roll our own. Apache Arrow looks like a pretty cool library. There's also this repo I found https://github.com/hosseinmoein/DataFrame/