added --ignore-violations-on-exit flag for easier CI reporting integr…

[g4z]

For our CI setup, we wanted to be able to run phpcpd from a bash script and have it exit with a 0 status code each time (so it doesn't cause the build process to fail). This is because we are using phpcpd purely for reporting.

I added a new optional command line argument: --ignore-violations-on-exit (this is the same syntax as the phpmd tool), which causes phpcpd to always exit with a 0 status code.

This may be useful to others. Please merge if you agree.

Regards!

[sebastianbergmann]

Thank you for your contribution but I do not think that this is the right way to achieve what you want. It would be better, IMO, to configure your CI to ignore the exit of PHPCPD.