Remove printed dict at looper finish

[donaldcampbelljr]

Currently looper prints a statement in dict format for the commands/jobs submitted:

Looper finished
Samples valid for job generation: 2 of 2
{'Pipestat compatible': False, 'Commands submitted': '2 of 2', 'Jobs submitted': 2}

I believe this was originally implemented such that looper would return this dict so that our pytesting could analyze it for accuracy certain tests. However, we would like to remove seeing this in the CLI when running looper.

[donaldcampbelljr]

This is now fixed by removing sys.exit(main()) and simply running main(). This does not hinder pytest results.