Reportseff

Fixed estimation of memory efficiency with multiple tasks.
A few source code improvements.

Thanks biermanr for help coding and angel-devicente for providing a test case.

Changed sacct delimiter to `^|^` so job names can contain a pipe without breaking.
Using reportseff's parsable option will still output a single pipe.

Change default to let click decide how to pipe color.

Added a discussion to the readme of how to handle the changes.

Thanks braffes for opening the issue at the PR!

Added more help for using the slurm-format option.
Handled cases where total time from the admin comment could be 0.

Thanks braffes for the bug report.

Added an option to specify the slurm output file format, accepting the format used by sbatch. This addresses using output names like `%j.out` which previously were ignored.
- `%j` or `%A` can be used to find the job id
- For array jobs, `%A_%a` must be present
- One of the above needs to be present or a value error is thrown as the jobid cannot be determined.
- Other, sequential format tokens are then collapsed into a single `.*`, e.g. `%n%x_%j.out` -> `.*_<JOBID>\.out`
- Any regex tokens in the format are escaped prior to processing and compiling.