Add option to have cloned node publish status default to unpublished

In my opinion, this is a very big usability improvement. Strange that this feature, which has low impact on the code, is not getting into the module.
When cloning nodes with translations, you don't want any incorrect translations being published.

Reroll of #11

I changed the clone_status field to a set of radios.

• Default
• Original
• Published
• Unpublished

Automatically closed - issue fixed for 2 weeks with no activity.