Hello, just to let you know I did some changes to enable userless access, feel free to ignore

[salgadobreno]

Hey, I liked this gem but I missed userless request for venues, so I did some refactoring to have it

Ive just saw that another dude did the same, apparently not issuing a pull request... maybe his take on it was better than mine! Anyway, I felt I wanted an API with class methods for this, like Foursquare::Venue.search(...) feel free to ignore this pull, but it would be nice to have userless access for the gem too!

refactor in all files to make userless requests avaible in the api, example: Foursquare::Venue.search(:client_id => x, :client_secret => y)