Prevent IDs on headlines from beeing removed
Prevent IDs on headlines from beeing removed

By default the declassify package removed IDs, because IDs are used as
anchors, this was a bad thing. declassify is now configured to only
remove unused CSS classes but not IDs.

Fixes #72

maoberlehner/markus-oberlehner-net,maoberlehner/markus-oberlehner-net