update README.MD

[kalenkovich]

• update to running the full workflow (probably with --keep-going)
• what to do with download errors (--until download_from_openneuro --restart-times 5)
• what to do with segmentation fault or python dying (see the resources issue)

[kalenkovich]

In case of errors in rule download_from_openneuro, use

snakemake --until download_from_openneuro --cores <n_cores> --restart-times 5

Then run the rest.

[kalenkovich]

In case of segmentation fault or Python dying while running jobs from rules apply_linear_filter and create_artifact_epochs, run

snakemake --cores <n_cores> --resources filtering_process=<n_cores> --default-resources filtering_process=1

The snakemake version that we use does not support --set-resources so we'll have to add them to Snakefile.