Removed silent : true from dummy_pane
Escape 's in javascript for report data
Added a flag for silent when deleting a question.
Notify Airbrake when there's a validation error while creating/updating a response.

- Only for APIResponsesController
Removed reduntant response.save which was causing validations to fail
Add Response#last_update.

- Find the time of the last update.
- Either the response itself or one of it's answers.
Show the time of last update for each response in the Responses#index page.
Show the `Last Updated At` date for a response in the excel output as well.
Show the address for a response in the Excel output.

The same address that's shown in the web view.
Render the question number with a question in the Excel output.
Show the IP Address for a response in the Excel output.
Show the organisation name for a response in the Excel output.
Filename for the Excel includes the survey ID as well.
`sort_questions_by_order_number` doesn't cause an exception if the sort fails.

It just puts the misbehaving elements at the beginning of the list.
Mock the `Organization.all` call in the ResponseController spec.

Fixes the build.
Check if there is a parent_question instead of checking if there is a parent option.
Check for `parent` AND `parent_question`.
Order the questions correctly in the excel output.
Disable the `complete` and `save as draft` buttons after the first click.
Show dates in the `03 Jan 2013` format.