Add d11 support

I added d11 support and fixed 1 critical issue while testing on D11.
Tested this by going through the settings form and just testing all the options.

I also think we can remove d8 support?

jonasanne → closed merge request !38

I closed the MR and made the changes in a patch.
Because of Tim, I noticed that this MR was not BC and would create errors on D8 and 9.
So there needs to be a major release with this patch.