better error message in case of missing uids
gnome-terminal 3.12: enable nautilus extension
Merge pull request #2782 from soenkehahn/better_error_message_missing_uid

better error message in case of missing uids
maintainers.nix: add missing edeoryd46, fixing channel

Close #2783.
flightgear & simgear: Bump to 3.0.0.