Point Of Interest (Quest Details etc.)

@wsuchy , @jacekjursza and me - decided to implement QuestDetails API and NearbyQuests API (+ all related stuff) in single brunch (because these tasks are strongly coupled).

At the moment - this pull request must be only reviewed and not merged!
I'm wondering how we should treat priority of this two params; Maybe they should be mutually exclusive - you must pass one of them, but passing both results in HTTP 400?