Blender Git Loki

Bugfix #4355

Group appending issue: the rules for how this works were still confusing.
In some cases you want the objects in the scene itself, in others not.

New method:

- when you append a group directly (shift+f1 -> group -> name(s)) it
will both append the group and link objects to the current scene
- in all other cases it will only append a group itself.
(means, you can then use "Add group" to see it).