Quote name correctly in query. Fixes #598.
API errors should be JSON

The API was returning Rails (HTML) errors for certain error
conditions, which is inconvenient because it makes it difficult
for the client to extract the error message.

This patch changes add_correspondence to return JSON errors
(still with suitable HTTP status codes) for two common exceptional
conditions, and adds tests.
Merge branch 'develop' of github.com:mysociety/alaveteli into develop
Merge branch 'hotfix/api-errors' into develop
Update other tests

Update the other API tests to take account of the changed error behaviour.
Merge branch 'hotfix/api-errors-2' into develop
Merge branch 'hotfix/0.6.5.1' into develop
gs-gpl is no longer in Ubuntu

Change it to ghostscript
capify .
Everyone is using Git
Remove comments
Add deployment tasks for Passenger
Make Capistrano configurable using general.yml
Order consistently
Use bundler via capistrano
Don't use sudo
Add a since_date parameter to the API feed
Clarify syntax
Move deployment configuration into its own file - thanks @crowbot!
Add a few more required options