Remove ujson dependency from setup.py?

[bmschmidt]

Trying to install on a wonky machine, I found I had to manually remove the entry for ujson from setup.py because I was having trouble compiling it.

In general, ujson is a dead package; it might be worth switching to orjson for speed. But since there's already a fallback to standard json in the code here, I don't think it would hurt to just remove it from the setup?

[organisciak]

I'll update this in the Massive Texts fork, since I'll be looking to merge that here in the coming month or so. orjson looks good - the built-in library was a bottleneck. The side benefit is that I can stop maintaining a conda package for ujson!

[organisciak]

... but looks like I'll have to build an orjson conda package.

[organisciak]

Updated massivetexts@7eae68a with rapidjson, which seems better supported.