* Make hardcoded limit for EDNS0 response size configurable (environment). * Add support for locations + timestamps to tinydns-sign (basically, treat them as separate zones, with timestamp-dependend SOA serials). * Add support for ((semi-)automatic) ZSK rollover using pre-publish method. * Refactor tinydns-sign: - separate generation of helper records - put some functionality into modules - make (better) use of existing Net::DNS modules