Getting rid of libgtk2.0-0png3

[Robert McQueen <robot101@debian.org>]

I've grepped the Packages files for {,non-US/}{main,contrib,non-free} on
all architectures and found that celestia is the only package in the
archive that depends on libgtk2.0-0png3. Given that this erroneously
created package has never existed in a released version of Debian, we
should get rid of the silly thing now before sarge gets too near
release, or we'll have to keep it around for another two!

All we need is an upload of celestia that build-depends on libgtk2.0-dev
(>= 2.0.6-2), and then we can make libgtk2.0-0 Conflict and Replace
libgtk2.0-0png3 so dpkg will get rid of it. Marcelo, can you do an
upload of celestia to do this, or do you want me to NMU it? Akira, will
you do these changes to Gtk+ when this is done?

Regards,
Rob