Extend MoonSharp userdata at script runtime

MoonSharp_UserData_Runtime_Extension

		public class MyObject
		{
			public int GetSomething()
			{
				return 10;
			}
		}

		[Test]
		public void MetatableExtensibleObjectSample()
		{
			string code = @"    

				--declare this once for all
				extensibleObjectMeta = {
					__index = function(t, name) local obj = rawget(t, 'wrappedobj'); if (obj) then return obj[name]; end end
				}

				-- create a new wrapped object called myobj, wrapping the object o
				myobj = { wrappedobj = o };
				setmetatable(myobj, extensibleObjectMeta);

				function myobj.extended()
					return 12;	
				end


				return myobj.extended() * myobj.getSomething();
				";

			Script script = new Script();
			UserData.RegisterType<MyObject>();
			script.Globals["o"] = new MyObject();
			
			DynValue res = script.DoString(code);

			Assert.AreEqual(DataType.Number, res.Type);
			Assert.AreEqual(120, res.Number);
		}