Allow specifying a User-Agent
While servers generally don't require a specific User-Agent to be set, some of them are protected by CloudFlare or other server proxies, which might block requests coming with certain User-Agents (or not having one at all). I recently got the issue with SmugSmug (see also this thread).
I think we should introduce a
UserAgent parameter which would define the User-Agent header to be set on all requests.
I'll take care of adding this to the signond OAuth plugin.