More space efficient serialization

[mpetri]

nice library. I remember the original ot code has compact_elias_fano codes where universe and num elems can be passed in during serialization to make the format more compact. this is especially important when we want to store many small lists where the overhead of storing these explicitly can be prohibitive.

Any plans for such structures?

[kampersanda]

@mpetri

Oh, I don't know that option. Thank you for the info! I'll investigate it, and if it has a significant impact, I'll add that option to sucds.