Instagram node

This is my attempt on the Instagram node. Current example is showing the query node. Comments are welcome. I'll squash commits once we get this work into a pullable state. Thanks

The pull request is now ready @knolleary .
I didn't consider "catch fault by testing" because testing a "re-init" scenario is something we haven't tested before in our unit tests (as far as I know). It's smells more like a component test. In order to have confidence in changing things like initialization behaviour, we'd need to write tests (component tests) that control/check the init behaviour.

I'll change the behaviour to the "fetch as little as possible" scenario. I'll consider this problem when adding the tests too. However we might need to make some kind of test architectural decision to see how we can ensure that such regressions are caught. Not sure yet.