Add missing kobo 0.5.0 release notes
Add missing kobo 0.5.0 release notes

Release notes were never filled in for 0.5.x major release.
It'd be nice to resurrect these before 0.6.x, so I've filled them in
best I can based on the commit log from 0.4.3..0.5.0.

release-engineering/kobo,release-engineering/kobo,release-engineering/kobo,release-engineering/kobo