Changed logging in DoTimed/RunActivity to create less overhead.

- Refactored PerfTimer to use less memory.
- Avoid using the PerfTimer in highly called methods DoTimed and RunActivity, instead tracking long ticks manually to reduce overhead and avoid memory allocations.
- Added some helper methods in PerfTimer to output information when a tick takes too long.
- Changed PerfTimer logging to output the time at the start of the line, and no longer truncate output per line.
- Settings.LongTickThreshold changed from TimeSpan to float and renamed to LongTickThresholdMs.

OpenRA.Game/World.cs

@@ -244,9 +244,9 @@ namespace OpenRA
 					foreach (var a in actors)
 						a.Tick();
 
-				ActorsWithTrait<ITick>().DoTimed(x => x.Trait.Tick(x.Actor), "Trait", Game.Settings.Debug.LongTickThreshold);
+				ActorsWithTrait<ITick>().DoTimed(x => x.Trait.Tick(x.Actor), "Trait");
 
-				effects.DoTimed(e => e.Tick(this), "Effect", Game.Settings.Debug.LongTickThreshold);
+				effects.DoTimed(e => e.Tick(this), "Effect");
 			}
 
 			while (frameEndActions.Count != 0)