subset_h5_list_by_observations: Subset a h5_list object based on a set of observations.
In AllenInstitute/BarMixer: Hashed scRNA-seq demultiplexing for .h5 files

Subset a h5_list object based on a set of observations.

subset_h5_list_by_observations(
  h5_list,
  match_values,
  match_target = "barcodes",
  sparse_matrices = "matrix"
)

`h5_list`	a list object generated by running rhdf5::h5dump() on a 10x HDF5 file.
`match_values`	a vector of values to use for filtering
`match_target`	a character object specifying which values to use for filtering in the h5_list. If "barcodes", uses matrix/barcodes; Otherwise, looks in matrix/observations for matching values
`sparse_matrices`	a character vector specifying which list objects to treat as sparse matrices. If these aren't currently dgCMatrices, they will be converted by h5_list_convert_to_dgCMatrix for filtering.