Squashed commit of the following:


Backport of #3946 in stable5

Some quick reviews please
@schiesbn @karlitschek @butonic @icewind1991 @MTGap THX

commit 70e6ad56ed5d00aeea8fe82b45047998dac92f80
Author: Thomas Müller <thomas.mueller@tmit.eu>
Date:   Sat Jul 6 00:11:42 2013 +0200

    fixing check if public share is a folder or not

commit 8e74ecec3f43a52a9a55871954171ef4073eab9d
Author: Thomas Müller <thomas.mueller@tmit.eu>
Date:   Sat Jul 6 00:04:01 2013 +0200

    removing unused getSharedItem()

commit 60ac0f274bbaa926dcec1800e952f2e0b1f05a50
Author: Thomas Müller <thomas.mueller@tmit.eu>
Date:   Fri Jul 5 17:39:41 2013 +0200

    on reshares we now recursively move to the root of all reshares - therefore some code has been refactured and added as a new public function

    Conflicts:
    	apps/files/ajax/upload.php

commit f071f7439568ffd8b785cd96035cc2e616f61b01
Author: Thomas Müller <thomas.mueller@tmit.eu>
Date:   Fri Jul 5 11:30:53 2013 +0200

    fixing Notice: Undefined index: isPublic

commit d2f2c7e9b896fd0ac57fb8047501205fc37b2abc
Author: Thomas Müller <thomas.mueller@tmit.eu>
Date:   Fri Jul 5 09:58:41 2013 +0200

    handle anonymous upload to reshared folder