BoUML was close sourced by its author and consequently dropped
from Debian. We use UML as a drawing and documentation tool,
and thus we'll just start over with the /obvious/ choice,
which is the Umbrello tool.
Remove some orphaned diagrams and PNG images not actually used
in the TiddlyWiki. Add a page with some hints regarding Bouml
See also #960 -- Bouml has been discontinued and is closed source now
not sure how to proceed with this