Squish out any reference to things by corpus_name

[ryaanahmed]

This is mostly for @sophiazhi, who's going through and making our analysis functions take Corpus objects directly as arguments, rather than taking a corpus_name.

Just a heads up for @samimak37. I think we keep corpus_name around (but probably rename to name since why type my_corpus.corpus_name when you can type my_corpus.name?), but stop relying on it for anything other than as a convenience when printing results.

[ryaanahmed]

done! thanks all. (there are a few instances of the string 'corpus_name' in the repo, but they're all in sensible places...)