#8 Unused modules should not be considered for mails

[Fabian Mandelbaum]

Modules not used by any active document should not be
considered for mails-with-todo-for-authors reports.

For example, I have received a mail from r2 stating
that I had to do synch for networking-chapter and
security-chapter in ES when those modules were not part
of any active document (the modules *are* part of an
active document, but ES *is not* active for that document).

Note: Even if non-active, I passed .revision
TYPE=translate for those modules in ES. I think
revision passing is OK, but TODO mails should not have
the above described modules into account.