shared-color-targets is missing, calibration doens't work

The shared-color-targets package isn't available in Ubuntu, so when GNOME Color Manager attempts to install it to make profiling cameras and scanners possible, the process simply fails.

Explanation: to profile a camera or a scanner you need a capture of a reflective calibration target which is, essentially, a cardboard with color patches printed on it. For each type of a target you need a text file that describes this target so that calibration/profiling software knows what and where to look for when reading the captured image. The shared-color-targets is a collection of such files.

Solution: provide shared-color-targets package, available at http://people.freedesktop.org/~hughsient/releases/. You don't have to make it a hard dependency, but installing it should work.