Coverage and dead files

[patrickmineault]

There's a few files with no test coverage, and some that are commented out. It's unclear whether I should assume that they're broken, that they might work but are untested, or that they haven't been migrated to the new sklearn-like interface. The files in question are:

netrep/rbf_sampler.py
netrep/conv_layers.py
netrep/kmeans.py
netrep/metrics/kernel.py

Either clarifying in text the status or deleting the dead files would work.