CRAN release 0.8.3

• mirai() gains the following enhancements (thanks @HenrikBengtsson):
  • accepts a language or expression object being passed to '.expr' for evaluation.
  • accepts a list of 'name = value' pairs being passed to '.args' as well as the existing '...'.
  • objects specified via '...' now take precedence over '.args' if the same named object appears.
• dispatcher() gains the following arguments:
  • token for appending a unique token to each URL the dispatcher listens at.
  • lock for locking sockets to prevent more than one server connecting at a unique URL.
• saisei() implemented to regenerate the token used by a given dispatcher socket.
• launch_server() replaces launch() for launching local instances, with a simpler interface directly mapping to server().
• Automatically-launched local daemons revised to use unique tokens in their URLs.
• Daemons status matrix headers updated to 'online', 'instance', 'assigned', and 'complete'.
• Fixes potential issue when attempting to use mirai() with timeouts and no connection to a server.
• Requires nanonext >= 0.8.2.
• Internal performance enhancements.