#i123964# mark add_to_recently_used_file_list() as DLLPUBLIC

so its symbol can be used for dynamic loading, e.g. in vcl
#i123817# replaced boost::shared_dynamic_cast in slideshow

Boost's shared_dynamic_cast and shared_static_cast were deprecated since
boost 1.35 and removed in boost 1.53, so they have to be replaced

Found-by: Ariel Constenla-Haile <arielch@apache.org>
Suggested-by: Ariel Constenla-Haile <arielch@apache.org>
Reviewed-by: Herbert Duerr <hdu@apache.org>