Unable to drag drop a folder named "0"

[marc-chappuis]

When uploading a folder named "0", there is an alert with the message:

Unable to create folder "".
Invalid file name.

The alert is also displayed twice

To reproduce the bug, create a folder on your computer named "0", add at least one file inside and
drag drop the folder to elfinder.

If you create a folder named "0" directly on elfinder it works.

If you drag drop a folder named "0" from your computer on an existing one on elfinder, it works after asking you if you want to replace it.

Was using chrome 51.0.2704.103 on windows 10

[nao-pon]

@marc-chappuis This is a bug of elFinder.class.php. I'll fix it.