class_docstr: A list of files built by on exploring the filesystem and filtered by
  applying various patterns to what we find there.
  
  Instance attributes:
    dir
      directory from which files will be taken -- only used if
      'allfiles' not supplied to constructor
    files
      list of filenames currently being built/filtered/manipulated
    allfiles
      complete list of files under consideration (ie. without any
      filtering applied)
code: def __init__(self, warn=None, debug_print=None):
      # ignore argument to FileList, but keep them for backwards
      # compatibility
      self.allfiles = None
      self.files = []
  
imports: import os, re
  import fnmatch
  import functools
  from distutils.util import convert_path
  from distutils.errors import DistutilsTemplateError, DistutilsInternalError
  from distutils import log
label_desc: Use image node_id 1 to create a new FileList object  with example: obj = FileList(warn, debug_print)