Enhancement: Allow resources to be a SourceFileList

Currently resources in a project need to be defined using [FileElement] which then precludes the option to exclude files from a particular directory. This is possible using the SourceFilesList used with the sources parameter.

It would be very nice if this could be an option.

BTW: I am reporting these kind of things here, rather than opening an issue, figuring it is not up to me to decide of such a proposal does become an issue to be worked on. Let me know if the preferences is otherwise.