Deal with dvdauthor bug that is currently breaking builds (#320195).

Improve audio quality
- Normalise volume.  There's a fair amount of variation between talks.
- Filter out high-pitched noise (feedback?) from some of the talks.

Integrate the band video and additional talk videos when they are
available.

Test and complete NTSC support.
- Menus need to be adjusted to NTSC resolution
- Audio may need to be recoded to AC3

Test dual-layer discs.

Add chapter marks (particularly for 2-part workshops/round tables).

Recut some videos that start too early or end too late
- Last few seconds of 2005-07-09/08
- ...

Arrange return to same menu after each video plays (I think this
may require "jump-pads").

Change title font to match Debconf logo better.  (This is problematic
- the font appears to be Sun Serif which is non-free and not even
meant for use outside Sun.)
