All 46 Dockerfile steps complete, 17/17 Python packages importable,
9/9 R Bioconductor packages loadable. Validated with:
  podman run --rm lopez:latest python3.7 -c 'import scanpy, anndata,
    louvain, leidenalg, h5py, rpy2, anndata2ri, tables, tiledb, ...'

Root causes fixed (see docker/CHANGES.md for full details):

System libraries:
- Added libigraph-dev, libhdf5-dev, libblas-dev, liblapack-dev,
  libopenblas-dev to apt-get (missing in original)
- Added cmake via apt-get (Debian 10 = 3.13.4) after python build to
  preserve layer cache; pip cmake>=3.17 wraps binary in Python entry-
  point that breaks MulticoreTSNE's subprocess cmake invocation

R packages:
- Set options(repos=...) in every RUN to fix BiocManager CRAN isolation
- Pre-install RcppArmadillo 0.9.850.1.0, igraph 1.2.4.2, irlba 2.3.3
  from CRAN archive (newer versions require cpp11/C++17, not in 2020)
- CXX14 Makevars to fix RcppAnnoy/BiocNeighbors under GCC 8....