Support for live reload

[scottcorgan]

superstatic --live flag

[rwjblue]

👍

[mbleigh]

I'm strongly in favor of landing LiveReload support, but we have some thinking to do about trade-offs.

1. LiveReload should only ever be used in a local/dev environment, not production. Because of that, it seems weird for it to be a dependency. How can we address?
2. Should this be implemented as a service? What does that look like? Can/should services be able to add command-line options?

[scottcorgan]

Closed by 01db093