Be able to check root files

Today, the Maven Checkstyle plug-in allows to verify files within the Maven directories: sources, test sources, resources and test resources.

In addition to this, I would personnaly like to verify my pom.xml file.
I have tried many things but I did not succeed in validating my POM files with Checkstyle. And looking at the code, I think I saw why.

The reason for such a verification is that this file also contains license headers that I would like to keep verified. And I am pretty sure there would be other rules I would like to check (such as indentation, etc).

If we consider other project kinds, such as Eclipse plug-ins, one may want to verify plugin.xml and feature.xml files. So, it would be nice to be able to specify otherIncludes in the plug-in's configuration. This new parameter would contain a list of files to verify, when they exist.

If the idea is accepted, I am ready to contribute a patch for this feature.