Document data types able to be visualized

[k8hertweck]

The documentation should specifically state what data types can be visualized in the browser. Ideally, we'd also include at least one example of the data (though we may include this in a separate repository, or instructions for downloading from a separate data publishing site, communicated through a vignette).

[k8hertweck]

Is it possible to combine data types to visualize? If not yet, then is that idea part of the roadmap?

[ergonyc]

This is a good question... Right now the "curation" process requires a level of mastery over the data being browsed which makes the question kind of moot.
I think what we are really needing to get at is: How can we import data to the AnnData format? I think the first step is to enumerate what data-formats people use / want to load and get after supporting their ingest...

Right now there are essentially two options with helper functions:

1. make the anndata from scratch with R data primitives - matrix + 2 data tables.
2. import from Seurat with sceasy

[k8hertweck]

Four main types of data are now documented in the README.

Mention in the README what example data are currently included. Documenting examples for other data types can come later.