Now KoResourceServer has a second template parameter that defines
the policy which should be used for storing a resource. There are
to predefined policies:

* PointerStroragePolicy --- usual pointers with ownership over
                            the resource.
* SharedPointerStroragePolicy --- shared pointers. The server does no
                                  extra handling for the lifetime of
                                  the resource.

Use the former for usual resources and the latter for shared pointer based
ones.