Prevent early initialization of mock from checking for delegate mocks.

Fixes issue #54

Author: kzu

Source/ExpressionExtensions.cs

@@ -238,7 +238,7 @@ internal static CallInfo GetCallInfo(this LambdaExpression expression, Mock mock
 		{
 			Guard.NotNull(() => expression, expression);
 
-			if (mock.DelegateInterfaceMethod != null)
+			if (mock.IsDelegateMock)
 			{
 				// We're a mock for a delegate, so this call can only
 				// possibly be the result of invoking the delegate.

Source/Mock.Generic.cs

@@ -139,11 +139,16 @@ private void CheckParameters()
 			get { return (T)base.Object; }
 		}
 
+        internal override bool IsDelegateMock
+        {
+            get { return typeof(T).IsDelegate(); }
+        }
+
 		private void InitializeInstance()
 		{
 			PexProtector.Invoke(() =>
 			{
-				if (typeof(T).IsDelegate())
+				if (this.IsDelegateMock)
 				{
 					// We're mocking a delegate.
 					// Firstly, get/create an interface with a method whose signature