Blender Git Loki

Bugfix #16535

The infamous Fkey 'make face' in editmode still failed in cases, giving
an annoying convex error popup.
Found two errors in this code:

- not all cases were evaluated to make a face of 4 vertices (6 cases)
- the function that makes always a face when the 4 edges already exist
failed when not in vertex-select mode.

I also removed the popup, but added a print... its still not perfect.