Add option to exit cleanly even if problems are found
Add option to exit cleanly even if problems are found

Some testing frameworks interpret tools exiting with a non-zero code as a
failure of the tool rather than the tests it performs, adding this option
allows panlint to be used with these tools. (e.g. arcanist).

quattor/pan,quattor/pan,quattor/pan,jrha/pan,jrha/pan,quattor/pan,quattor/pan,jrha/pan,jrha/pan,jrha/pan