Added configuration option ``unreleased_version_title`` with
associated Sphinx directive argument to control whether to show the
computed version number for changes that have not been tagged, or to
show a static title string specified in the option value.
Change-Id: I3069a008451e93cb62e5e43611cf62de5026952f
Signed-off-by: Doug Hellmann <doug@doughellmann.com>
187d586d5f