Show Health bar when attacked or healed

By LadylexUK

Add to player or NPC brains

1. WHEN [health][changed] DO [boolvar:show health][equals][true]
2. WHEN [boolvar:show health] DO [display meter][blue][heath][above][small HUD]
3. …WHEN [countdown timer] DO [boolvar:show health][equals][false] // Add a number to the countdown timer for a longer reveal