Request responses should parse internal dicts into Resource instances

[samamorgan]

The JSON structure of many responses include additional objects that this library isn't fully parsing, creating a slightly awkward situation where we're using both dot notation and dict key lookups.

# Pseudo-code
encounter = Patient().Encounter().get()

status = encounter.jsonBody["status"]
status = encounter.jsonBody.status  # AttributeError

The response parser should also attempt to resolve nested dict and list into Collection and Resource