Add 'lang::message::undelete', in order to provide an API for undeletion of messages deleted via 'lang::message::delete', and modify 'lang::message::edit' accordingly. Next step would be to provide a user interface for it.
rework acs::test::http interface to allow daisy chaining of requests. One can now specify "-last_reqest" to let a new http to continue with the same credentials (e.g. cookies) as the last request. The old interface based on "-user_id" continues to work