v1.0.0-beta4

• [Breaking] Monolithic framework, as released in initial betas, has been
  broken into smaller pieces as a result of recent advances in dig library.
  This is a radical departure from the previous direction, but it needed to
  be done for the long-term good of the project.
• [Breaking] Module interface has been scoped all the way down to being
  a single dig constructor. This allows for very sophisticated module
  compositions. See go.uber.org/dig for more information on the constructors.
• [Breaking] package config has been moved to its own repository.
  see go.uber.org/config for more information.
• fx.Lifecycle has been added for modules to hook into the framework
  lifecycle events.
• service.Host interface which composed a number of primitives together
  (configuration, metrics, tracing) has been deprecated in favor of
  fx.App.