added foursquareinteractionmodel

removed ajax call from whereami.js and created standalone
4sq-interaction-model (captureVenues)

ToDo: implement
  - 4sq-Venue-Model (single venue of collection)
  - 4sq-Venue-View (single venue view)
  - 4sq-Venue-Collection (all venues of captureVenues)
  - 4sq-Venues-View (all venues of collection view)