Add option to pass additional parameters when submitting jobs to the grid

[lrauschning]

Hi, our local slurm cluster is configured in such a way that additional parameters are required when submitting jobs, and the job ID may contain a semicolon. This commit enables additional parameters to be specified as a snakemake resource (clusterparams) and handles job IDs containing a semicolon (this was causing issues as the semicolon was causing part of the ID to be interpreted as a new command). I've also added a notice to the help message, in case other users run into this same issue.

[brianwalenz]

Thanks!

Can you give an example --snakeopts for setting clusterparams?

I'm going to make some changes before merging - mostly just promoting the grid parameters to their own verkko option instead of passing through --snakeopts.

[lrauschning]

No problem! For use in our cluster, I pass --snakeopts '--default-resources clusterparams=\"-M\ biohpc_gen\ -p\ biohpc_gen_highmem\"' to select the appropriate cluster and the highmem queue, though other users might also want to specify their account or other slurm options.

[skoren]

I think this is handled by the latest code (e.g. issue #209, #219, #257 and others). I've added this info to the README.md