Withdraw the change that Fred just checked in -- it was a poorly
documented feature, not a bug, to ignore I/O errors in read().

The new docstring explains the reason for the feature:
"""
this is designed so that you can specifiy a list of potential
configuration file locations (e.g. current directory, user's home
directory, systemwide directory), and all existing configuration files
in the list will be read.
"""

Also add a lower-level function, readfp(), which takes an open file
object (and optionally a filename).

XXX There are some other problems with this module, but I don't have
time to dig into these; in particular, there are complaints that the
%(name)s substitution from the [DEFAULTS] section doesn't work
correctly.