add uns

[rcannood]

• Add .uns slot to AnnData classes.
• Add roundtrip tests for .uns. Parts of the tests that are not working are disabled and marked with a # TODO:. These should be re-enabled in future PRs.
• Improvements to how logicals, factors and/or scalars get read and written.

[rcannood]

@lazappi Shall we merge this PR so other conversion functions (Seurat & SCE) can already start using the uns?

[lazappi]

I'm still working through the things that are failing. Some of them are actually due to the Seurat conversion so I was going to suggest that should be merged first. Maybe that's not so easy though.

[rcannood]

I'm still working through the things that are failing. Some of them are actually due to the Seurat conversion so I was going to suggest that should be merged first. Maybe that's not so easy though.

Fair enough!

I merged a PR that skips the Seurat-related unit tests. Maybe the remaining issues are easier to fix, now ☺️

[rcannood]

I merged the main branch into this one, which splits up the different roundtrip tests based on data type. This allowed me to disable the data types which result in errors. If these tests passes, I'll merge the PR. Then, I'll create separate PRs which re-enable the failing tests per data type that is broken.

[lazappi]

Ah, ok. So which branch should I work on? There were some fixes on this branch which I don't think have been merged (and others I haven't finished yet).

[rcannood]

Oh -- I apologize for merging this branch too quickly and any inconveniences I have caused!

In preparation for tomorrow's meeting, I created a bunch of PRs where each of the problems I encountered due to the extended tests (PR #137).

Perhaps the fixes implemented already fixes some of these issues 🤞

Feel free to push your changes to a new branch, or whichever branch you think is most suitable for your efforts. Thanks!