Better options for Real Time DPS

- Removed 'Real Time DPS' from the time measure dropdown.
- Added "Show 'Real Time' DPS" toggle to show real time dps while in combat.
- Added "Order Bars By Real Time DPS" toggle to order bars by the amount of real time dps.
- Added "Always Use Real Time in Arenas" toggle to always use real time dps in Arenas.
- Added .last_dps_realtime to player actors, caches the latest real time dps calculated.

Libs/DF/slider.lua

@@ -1178,6 +1178,8 @@ function DF:NewSlider (parent, container, name, member, width, height, minValue,
 		if (label_template) then
 			label:SetTemplate(label_template)
 		end
+
+		SliderObject.label = label
 	end
 
 	if (slider_template) then