Fix #782: Make doctest work with new configparser versions

Upstream changeset http://hg.python.org/cpython/rev/791674a74e47
switched format from %s to %r, so we need to add some ellipses
to work with both old and new versions.
Merge pull request #784 from mitya57/master

Fix #782: Add missing quotes for filenames in doctest
Update the changelog.