- add implementation of abstract factories

IRegistrationBase.md

@@ -69,3 +69,14 @@ It consists of the implemented properties from the [`IRegistrationBase`](IRegist
 ```c#
 ITypedFactory<TFactory> Factory { get; }
 ```
+
+The `TypedFactoryRegistration<TFactory>` class implements the `ITypedFactoryRegistration<TFactory>` interface and also handles the implementation of the abstract factories. Therefore it supplies the `CreateFactory()` method:
+
+```c#
+private void CreateFactory(IIocContainer container)
+{
+
+}
+```
+
+This is done by writing the IL code for the `Create()` methods manually that call the `IocContainer.Resolve()` method, as well as the `ClearMultitonInstance` method that calls the `IocContainer.ClearMultitonInstances<>()` method.