[WIP] Add two feature sampling methods for graphs

[j1c]

These are two methods for graph valued data.

1. Graph-Edge-MORF randomly takes one row of the adjacency matrices, then randomly samples some number of elements of that row based on patch_height_min and patch_height_max. The sum of the selected elements is the new feature for that graph.

2. Graph-Node-MORF randomly samples n \in [patch_height_min, patch_height_max] integers between [1, image_height]. You take the rows and cols based on the sampled integers, and sum the values in that small square. This is the new feature for that graph.

[netlify[bot]]

Deploy preview for rerf ready!

Built with commit b5839d10097adeca031ac529a14b6395049005a9

https://deploy-preview-337--rerf.netlify.com

[j1c]

Not quite sure how to deal with different sized tabs cause tabs in C++ files vary in size. Can be 8 spaces or 4 or 2....