The watched list resource is a special resource that exists only to link

to the other watched item resources. It was completely broken, returning

HTTP 405, due to a bad implementation of our singleton resource pattern.
This change fixes that up to use the correct method name, and

reimplements the body of it to skip the bulk of what the base get_list

implementation would have done.

Fetched the watched list resource and got a response with links instead

of an error.