Re-render the file-uploader after a successful image upload.

This allows an already-uploaded image to be replaced by another image.
Doing this after a refresh doesn't work, though.
Use the custom success/error callbacks in the Question model even during the initial fetch.

This allows image upload right after a refresh.
Change the zindex for the small notification spinner so it shows up UNDER the overlay window.
Fix a bug where save would fail after deleting a sub-question.
Update README.md with setup instructions.
Don't allow deletion of a published survey.
Added CanCan authorization to survey API controller
Added CanCan ability control for Response API controller
Added errors to 'photo' field for a mandatory photo question
Show the add_response link with apt cancan permissions
Added CanCan for QuestionController
Removed capaybara specs as they don't work with CanCan Authorization
Added CanCan Authentication for Option controller
Added latitude and longitude columns to the Response table
Merge branch 'master' of github.com:c42/survey-web
Added specs to the response model for attrs longitude and latitude
made latitude and longitude mass assignable
Added location to Responses#index
Added geocoder gem to get the location from latitude and longitude
Added reverse geocoding and storing the location in the Response model