Discovery of new cell annotations from single cell gene expression data

[dmccloskey]

As a user, and after annotating my cells with existing databases #40, I would like to be able to identify new cell types from single cell gene expression data. I would like to use common clustering algorithms and thresholds defined by common clustering metrics to define clusters. I would like to be able to visualize the clusters (and sub clusters) on a UMAP plot. I would also like to visualize the discovered annotations using a matrix bubble plot that shows the gene expression values of cell types (i.e., x axis would be genes, y axis would be cells, and bubbles would be gene expression values).