WIP: Coalesce profiles credentials agents

[iainkirkpatrick]

builds from #28

currently blocked by a TypeError when running this branch in conjunction with https://github.com/root-systems/dogstack-example/tree/upgrade-deps using npm link locally.

• the error occurs when the app first starts, thrown by subscribeTo.js inside rxjs, stating 'You provided an invalid object where a stream was expected. You can provide an Observable, Promise, Array, or Iterable.'
• commenting out the epic as agents combined epic that dogstack-example imports (in it's top-level epic.js file) removes the error, which leads me to consider the error is caused by dogstack-agents
• however, trying to isolate further by commenting out any of the agents, authentication, or relationships epic from inclusion in the exported combined epic from dogstack-agents doesn't have any effect - the error still shows up
• the only real other hint i have is that by logging result in subscribeTo, i can see that the function is called twice when the example app first loads - once with an Observable that has an operator property of 'ObserveOnOperator', and then secondly with an Observable that has an operator property of 'MergeMapOperator'. The second Observable is the one that doesn't meet the condition of result instanceof Observable_1.Observable inside subscribeTo.

@ahdinosaur .... are you likely to have any time to look at this over the next couple of days? it's driving me nuts, i'd be hoping you'd see something / know something that I don't that could lead down the joyful path of solution :)