[ubuntu-art] Breathe "Submissions" page cleanup.

[Cory K.]

For now, I'm calling Sebastian's trashcans final. So I'm removing them
and the other submissions from the page. When I return from Mexico in 2
weeks I hope to add Sebastian to the breathe-dev team and he can push
himself. :)

I've also removed the "start-here" submission as it doesn't fit with the
set and the colorless Rhythmbox icon.

-Cory K.