FIX: IsFolder -> isFolder
FIX: IsFolder -> isFolder

commit 9672f2862ced77516b154389c75281bd020c22d5 introduced an error in
getter/setter

camfindlay/silverstripe-docsviewer,camfindlay/silverstripe-docsviewer,dhensby/silverstripe-docsviewer,dhensby/silverstripe-docsviewer,silverstripe/silverstripe-docsviewer,silverstripe/silverstripe-docsviewer