Allow a custom logger to be provided

[Rowno]

This adds a new logger option that allows people supply a custom logger function. This is useful for people that use a structured logger like winston and also allows people to send errors to an error tracker like Sentry.

I also deleted the yarn.lock because the CI is using npm, not yarn.

[austinlparker]

Hey, this looks good - I went ahead and manually merged it because the built files got out of whack.