Added interactable property to Menu command

Allows you to add Menu options that are not selectable by the user
(e.g. they option is not available yet).
https://trello.com/c/bFjmGfBc

Assets/Fungus/Narrative/Scripts/Commands/Menu.cs

@@ -26,6 +26,9 @@ namespace Fungus
 		[Tooltip("Hide this option if the target block has been executed previously")]
 		public bool hideIfVisited;
 
+		[Tooltip("If false, the menu option will be displayed but will not be selectable")]
+		public BooleanData interactable = new BooleanData(true);
+
 		[Tooltip("A custom Menu Dialog to use to display this menu. All subsequent Menu commands will use this dialog.")]
 		public MenuDialog setMenuDialog;
 
@@ -50,7 +53,7 @@ namespace Fungus
 				{
 					menuDialog.gameObject.SetActive(true);
 					string displayText = text;
-					menuDialog.AddOption(displayText, targetBlock);
+					menuDialog.AddOption(displayText, interactable, targetBlock);
 				}
 			}
 

Assets/Fungus/Narrative/Scripts/MenuDialog.cs

@@ -91,9 +91,8 @@ namespace Fungus
 			}
 		}
 
-		public virtual bool AddOption(string text, Block targetBlock)
+		public virtual bool AddOption(string text, bool interactable, Block targetBlock)
 		{
-
 			bool addedOption = false;
 			foreach (Button button in cachedButtons)
 			{
@@ -101,6 +100,8 @@ namespace Fungus
 				{
 					button.gameObject.SetActive(true);
 
+					button.interactable = interactable;
+
 					Text textComponent = button.GetComponentInChildren<Text>();
 					if (textComponent != null)
 					{