[wip]Making swarm query node always return checkin

@hbeeken , as discussed with @knolleary today, the query nodes will always have to return something. Therefore I modified the Swarm query node to ensure that its behaviour is consistent with what I implemented in the Instagram node.

Started working on this too as @hbeeken is out of office until Wednesday. Also did some tidy-up whilst I was there.

I expect the unit tests to fail (although the node looks to be working OK) so hence the WIP tag until I get those working.
I havent yet reviewed the specific chnages here, but the discussion was along the lines of....

The requirement was to always return the users most recent check in, even if it has been returned previously. There are two possible uses. First, a flow needs to know the details of the latest check in (where is the user now?). Second is to do something because they have checked in somewhere new. If the node only returns unseen checkins, then the first scenario isn't possible. If the node always returns the latest check in then it is fairly simple to determine if it is 'new' or not.

You are right the docs need to reflect the behaviour.