Email authentication
Merged
Merged with gae-init
Merged with gae-init
Merge pull request #215 from lipis/auth

Email authentication
Pre-release version 1.2.3
Used Flask-RESTful for API.
Fix fields type.
Improved API errors handler.
Added request.query_string value to JSON link.
Added 'check_unique_email' field to config API.
Sorted properties in CONFIG_FIELDS.
Added recaptcha fields.
Minor fix.
Sorted User fields.
Update CONFIG_FIELDS.