Handle unreliable health values from RareCoordinator
Don't re-publish messages that were shared by own character
Hook onUpdate so we can provide periodic updates

Sometimes the rares health won't be changing (eg. you're chasing
Evermaw, but not attacking until your friend gets there), so this period
update (every 5 secs) allows updatig of coordinates without re-firing
the Target event
Removed stale comment from copy/paste
Support showing Decay events in debug chat
Only share Alive/Dead messages with others

(They'll handle decay themselves)
Decay events after 5 minutes of no updates

Information will be stale; so don't direct people there!
Move clone function to Common for reuse

SlashHandler needs to send new messages each time
Better logging and some minor fixes
Separate out sharing/announcing bools
Reorder test includes, so RareShare can access CreateFrame
Tidy up naming to avoid confusion between announce/share
Swap logic of SuppressAnnounce/AllowAnnounce
Add flag to allow announcing of external events

Generally this will have to be disabled to avoid lots of people
announcing the same events. However, if only one person (eg. me!)
enables it on a server, it won't be spammy, but will provide
announcements :)