LuaInterface: fix regression of optional parameter binding. (gui.text, for example)

LuaInterface/LuaInterface/CheckType.cs

@@ -108,7 +108,7 @@ namespace LuaInterface
                 if (LuaDLL.lua_isboolean(luaState, stackPos))
 					return extractValues[runtimeHandleValue];
             }
-            else if (paramType == typeof(string))
+            else if (paramType == typeof(string) || paramType == typeof (char []))
             {
                 if (LuaDLL.lua_isstring(luaState, stackPos))
 					return extractValues[runtimeHandleValue];

LuaInterface/LuaInterface/Metatables.cs

@@ -821,7 +821,7 @@ namespace LuaInterface
                 {
                     paramList.Add (null);
                     outList.Add (paramList.LastIndexOf (null));
-                }  else if (_IsTypeCorrect (luaState, currentLuaParam, currentNetParam, out extractValue)) {  // Type checking
+                }  else if (currentLuaParam <= nLuaParams && _IsTypeCorrect (luaState, currentLuaParam, currentNetParam, out extractValue)) {  // Type checking
                     var value = extractValue (luaState, currentLuaParam);
                     paramList.Add (value);
                     int index = paramList.LastIndexOf (value);