added gitignore to exclude .idea, and composer files
Added a cUrl option to capture cUrl request response headers. The main interest in the response headers is to capture the "X-RateLimit-Remaining" and "X-RateLimit-Limit" headers returned by the Foursquare API.
changed composer.json to match sazze/php-foursquare
added LastUrl field to help with debugging requests
include merge, but keep composer.json at hownowstephen/php-foursquare (nice try!)