added units.ini (and campaignUnits.ini), and IniFile got support for load/merging multiple files.

- Rules can now handle map-specific rules changes
    - units.ini replaces {buildings,units,infantry}.txt (or will replace; sidebar still uses them)
    - Added support for loading map-placed units/structures - try scg11eb.ini
        - added FCOM

OpenRa.Game/TechTree/Item.cs

@@ -41,7 +41,6 @@ namespace OpenRa.TechTree
 
 		static Tuple<string[],string[]> ParsePrerequisites(string prerequisites, string tag)
 		{
-			Debug.WriteLine( tag );
 			List<string> allied = new List<string>(prerequisites.ToLowerInvariant().Split(
 				new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries));