Switch to Rekognition API V2 and Fix Tests

* Use Rekognition HTTPS endpoint by replacing RestClient with Faraday and Excon adapter
* Use file(1) to get image content type for Faraday::UploadIO
* Stub Faraday requests with VCR and update VCR configuration
* Remove unused VCR cassette requests
* When Mustachio.face_data receives a Dragonfly::Job, ensure a temp_object is set
* Mustachio::Rekognition#face_detection finds mouth not eyes
* Mustachio.face_data returns an Array
* Pend "#face_data_as_px" since big_mouth_x is not 5.0 within small_mouth_x * scale
* Pend specs which test commented code
* Ignore VIM swap files
* Add Travis CI
remove ambiguous pending spec
upgrade gems
lock activesupport version for ruby 1.9.2 support
can't use :github syntax for heroku's version of bundler