
* make it possible to set the colors of the graphs from outside
* more tests
* Needs patch(es) to GD::Graph:
  - graphs with angled text at the bottom (like 45° since the email addresses or
    filter rules are pretty long)
* The sample script can not generate yearly/monthly stat. Bug in Mail::Graph,
  or GD::Graph?
* Bug: Sample does not generate last_x_days.
