Refactored IQuantizeBodyOrientation implementation

Moved BodyOrientation and related interfaces from Game to Mods.Common.
Introduced QuantizeFacingsFromSequence trait.
With*Body render traits no longer implement IQuantizeBodyOrientation
themselves.

OpenRA.Mods.Common/Effects/Contrail.cs

@@ -12,6 +12,7 @@ using System.Collections.Generic;
 using System.Drawing;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Graphics;
+using OpenRA.Mods.Common.Traits;
 using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.Effects