Move --contains test filtering logic into Julienne

[bonachea]

Currently significant --contains test filtering logic appears in the application's test code, but this goop should really be handled inside Julienne's test_description_t%run()

[rouson]

PR #86 accomplishes this.

[bonachea]

I've linked the issue to the PR, so that merging the PR will automatically close the issue.

In the future you can also accomplish this by adding key phrases to the PR description, like "Fixes #67"