Apple has quietly added space gray as a color option for the iPod touch 32GB and 64GB models, iPod nano, and iPod shuffle, replacing the previously slate black versions of each device. The new color option is sold as a color option for the devices at the same prices as before. Considering the unannounced color addition, it’s unlikely that Apple will further update their iPod line this year. In 2011, the fourth-generation iPod touch skipped a…