The createConfig function was looking in config/ directory when it should be looking in config/core/ directory.
Fixed methods to match their extended counterpart. Prevents php notices.
Changed DB define to MDB2 define.
Changed \e directive in preg_replace to a preg_replace_callback to prevent deprecation warning.
nextId would not check for existence of sequence schema prior to getting the next ID. Instead it would rely on an error result to determine the next action (creation of the sequence table). Script now checks for table's existence prior to asking for id.