Announcements documentation

• Announcements - META.yml
• Announcements Makefile.PL
• Announcements - communicate across the object network  [view source]
• Announcements::Announcing - role for objects which announce events  [view source]
• Announcements::Subscription - a subscription to a class of announcements  [view source]
• Announcements::SubscriptionRegistry - a registry for an object's subscriptions  [view source]