Blender Git Loki

Fix selecting multiple files ignoring first file

E.g. box selecting wouldn't allow selecting the first file.
Work selection and shift/ctrl selection had similar issues.

Code assumed that the first item was the '..' parent item and manually
removed it from the selection. I could just remove this special
handling, but instead I made the behavior more dynamic. So the file list
checks if the '..' item is there and only then applies special
treatment.
That way we can easily bring the '..' item back or make it optional if
wanted.