2.3.0 Beta 4

• Removed unnecessary Promises nesting
• Used ES6 class syntax for NodeModule class
• Forbid timeout larger than or equal to 2147483648ms for "/remindme" command due to the hard limit of Node.js Timers API. See https://nodejs.org/api/timers.html#timers_settimeout_callback_delay_args
• Forbid timeout of 0ms for "/remindme" command as it doesn't make sense to be reminded immediately... and because of the hard limit of Node.js Timers API. See https://nodejs.org/api/timers.html#timers_settimeout_callback_delay_args
• Added handler for unhandledRejection event, errors from unhandled rejected Promises will be logged
• Added missing command variations to help string
• Changed program flag "restartOnFatalError" to "--restart-on-fatal-error" to be consistent with node flag syntax. See https://nodejs.org/api/cli.html#cli_options
• Added handlers for "SIGHUP", "SIGINT", "SIGTERM", and "SIGBREAK" for clean shutdown
• Added "inviteURL" configuration, /invite command will only work if configuration is set. This is part of the effort to gradually phase out customization on Chillbot and commit back to upstream or sibling branches
• Added "--throw-deprecation" node flag to npm start script, as deprecated usages aren't encouraged especially for small projects like Chillbot
• Fixed version format, there's a "." between alpha/beta/rc and the number now. See https://semver.org/#spec-item-9
• Changed accepted format of version number for "/changelog" to reflect the change stated above
• Replaced if... return... statements with condition shorthand syntax
• Removed unused args at line 429 (now 434) and line 615 (now 620)
• Bumped version to v2.3.0-beta.4