wb_presets: Panasonic DMC-G6 (thanks to Gerd)
(cherry picked from commit 5b8f78a49a1eca7dc03f8fb05385dd700294aa1e)
rawspeed: Panasonic DMC-G6 aspect ratio support
(cherry picked from commit fdedf9abcae01992279c3ca3e7845da692c733f5)