[merge] add gnu changelog format with 'log --format changelog'

[Bundle Buggy]

Bundle Buggy has detected this merge request.

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3Ce01316480903021803x43eb073u84bcbc6540410528%40mail.gmail.com%3E
Project: Bazaar