Add KeyInput.IsRepeat.

OpenRA.Game/Input/IInputHandler.cs

@@ -69,5 +69,6 @@ namespace OpenRA
 		public Modifiers Modifiers;
 		public int MultiTapCount;
 		public char UnicodeChar;
+		public bool IsRepeat;
 	}
 }

OpenRA.Platforms.Default/Sdl2Input.cs

@@ -170,7 +170,8 @@ namespace OpenRA.Platforms.Default
 								Key = keyCode,
 								Modifiers = mods,
 								UnicodeChar = (char)e.key.keysym.sym,
-								MultiTapCount = tapCount
+								MultiTapCount = tapCount,
+								IsRepeat = e.key.repeat != 0
 							};
 
 							// Special case workaround for windows users