1.5.6

• jdbc: DB_READONLY=true env var can be used to make the whole app read-only (e.g. when migrating the DB, instead of Heroku maintenance mode)
• jdbc: CrudRepository.get() now has optional forUpdate parameter
• HttpExchange.fileName() added for setting of Content-Disposition
• json bugfix: json within json (and '') are now properly escaped
• json bugfix: render Any type as 'any' instead of 'string' in TSGenerator
• csv: new module for CSV parsing/generation