'Adds files to the project.
Args:
files: A list of Filter objects and/or relative paths to files.
This makes a copy of the file/filter tree at the time of this call.  If you
later add files to a Filter object which was passed into a previous call
to AddFiles(), it will not be reflected in this project.'

def AddFiles(self, files):

    self._AddFilesToNode(self.files_section, files)
