Checking if the email already exists
Version 1.0.12
Merge pull request #200 from lipis/email

Checking if the email already exists
Bumped pre-release 1.0.13 version
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.