Adjust UI to remove arg --repodir

[jeipollack]

-h, --help            show this help message and exit
  --conffile CONFFILE, -c CONFFILE
                        a configuration file containing program settings.
  --repodir REPODIR, -r REPODIR

During PR,
@sfarrens sfarrens last week
Why do we need to specify this?

While the code can be called from anywhere, the dataset files and SEDs are in sub-directories inside the repo dir. I guess it could be specified in the config file. I will think about it some more.

The batch job script executes the command cd $WORK/wf-psf before running WaveDiff to put us at the directory level. For the datasets, I see only the relative path is specified. It does appear that the repodir arg is only used to retrieve the logging config file.