This constructs a meta cell atlas object
mcell_new_mcatlas(
atlas_id,
mat_id,
naming_type,
mc_id,
graph_id,
gset_id,
type_annot
)
id matrix object
gene name type
id of metacell object
id of cgraph object
id of feature gene set
data frame with type_id, type_name, type_color fields
the knn parameter for neighbor type distribution