Fix MvcScaffolding unit tests failing to compile.

Added explicit GetEnumerator() method to CodeElements interface to fix MvcScaffolding unit tests failing to compile.

src/AddIns/Misc/PackageManagement/SharpDevelop.EnvDTE/Src/CodeElements.vb

@@ -8,5 +8,7 @@ Namespace EnvDTE
 		ReadOnly Property Count() As Integer
 		
 		Function Item(index As Object) As CodeElement
+		
+		Function GetEnumerator() As IEnumerator
 	End Interface
 End Namespace