CWR* and AR1 optimizer initialization

[AntonioCarta]

CWR* and AR1 can either use an optimizer passed by the caller, or create one with the lr and momentum parameters.

I think the optimizer should not be an argument because right now they are silently overriding the user's choice. Let me know if there is any reason for this otherwise I will remove the parameter.

[vlomonaco]

that's a bug. The user should be able to change them!

[AntonioCarta]

Actually, I was wrong. I checked again and everything is working as expected. Sorry for the mistake, I was probably confused by the double call to the parent constructor.
CWR* and AR1 have a slightly different interface compared to other strategies w.r.t. optimizer initialization but there is nothing wrong with it.

I'm closing the issue.