#198 Default audio cd size is uncommon

[Anonymous]

Reporting from downstream
https://bugs.launchpad.net/ubuntu/+source/gnomebaker/+bug/77680

When creating an audio cd project, the default medium size is 21 minute.
This could be an usability issue, since most users will probably be using a 74 or 80 minutes disc
and have to change every time the setting.

Proposed solutions:
1. Set the default to something more sensible, i.e. 74 or 80 minutes
2. Have gnomebaker remember the size of the last disc created