v0.8.0

Added

• Add transition callback. A function which is called for every transition. It has default empty
  implementation.
• Add support for implicit and wildcard internal transitions

Changed

• [breaking] Renamed custom_guard_error flag to custom_error as it is not guard specific anymore
• [breaking] Re-ordered on_exit/on_entry hooks calls
• [breaking] New transition_callback has replaced log_state_change as it is more flexible.

Full Changelog: v0.7.0...v0.8.0