'Update the index for the list of files in the project.
"nice" (default False) is a boolean indicating if this
update process should attempt to keep the CPU load low.'

def update(self, nice=False):

    if nice:
        XXX
    dirs_from_basename = {}
    for (dirpath, dirnames, filenames) in os.walk(self.proj.base_dir):
        for filename in filenames:
            dirs_from_basename.setdefault(filename, []).append(dirpath)
    self.dirs_from_basename = dirs_from_basename
