Periodically garbage-collect auras in the state machine.

diff --git a/OvaleAura.lua b/OvaleAura.lua
index f06ffcf..859a88f 100644
--- a/OvaleAura.lua
+++ b/OvaleAura.lua
@@ -511,6 +511,10 @@ end

 -- Reset the state to the current conditions.
 function OvaleAura:ResetState(state)
+	-- Periodically garbage-collect auras in the state machine.
+	if not Ovale.enCombat and state.serial % 1000 then
+		self:CleanState(state)
+	end
 	state.serial = state.serial + 1
 end