Sending is disabled in dev or test

[danielkhan]

Hello,

thank you for creating this module.

Inside notifier.js you write: // as you don't want to send emails while development or testing and then you disable sending for NODE_ENV = test or development.

I think it isn't a good idea to disable sending in development mode and if you do so you should mention this in big red letters inside the docs as people like me spend hours to figure out why no e-mails arive.

I would suggest adding a dry-run config option and default it to true. So people can decide.

[madhums]

sorry for this. will add a config option

[pft]

Added this config option in 9b9e81d67c9e4a4dc84b0836ca20c6d2bb4f347f