Changes to the change-history.

Since version 5.0.0 the support for a translated change-histroy has
been dropped. Also the source format for the history is now in
org-mode (e.g. version-5.0.0.org) and the resultung HTML needs to be
pasted into the not anymore generated change-history.htm4 file. The
one-page change-history has been kept for easier searching. new
release will also have a generated version-x.y.z.html file wit just
the release notes for a certain version.