Support for notName() method, from symfony component.

Hello,

I would like to add support for notName() method from symfony component at finder-facade project.
 Such support would be usable (I will going to add pull request based on this change to phpcpd project). 
In my use case, I have projects (drupal based), with a lot PHP files generated by application. Those files are very often similar to each other, so phpmd reports a lot of warnings about duplicated code.

Files created by developers and application are mixed together in same directories, and they have common extensions (ie *.inc). I'm not able to select only interesting, manually created files. As a solution, I think that support for additional parameter (both in application - phpcpd, and in library, as a dependency), that allows us to filter out files matching additional pattern(s) will resolve my issue.

Best regards