Decode classnames; they're encoded to be URL safe
Decode classnames; they're encoded to be URL safe

As per the documentation at:
https://httpd.apache.org/docs/2.4/mod/core.html#allowencodedslashes
Apache will intant 404 any URI that contains an encoded slash.
This is not allowed to be in a .htaccess file, so a configuration
alteration at core is not really an option. Luckily for us PHP
class names cannot contain a hyphen - so this is the recommended
way of dealing with this type of URI Parameter. This means we need
a single line to deal with this when handling the request though.

arillo/silverstripe-dataobject-preview,arillo/silverstripe-dataobject-preview