platinum: add xbmc specific fields dateadded, rating, votes and studio in MediaObject

xbmc:dateadded to pass dateadded with items and not need to stat upnp resources for that
xbmc:rating for number-based rating
xbmc:votes for string-based votes number
xbmc:studio for an string-based array of studios
platinum: add SearchSync method to SyncMediaBrowser
platinum: extend default browse/search filter
upnp: set SearchCapabilities of UPnP server to "upnp:class"
platinum/upnp: implement GetSearchCapabilities in media browser
upnp: improved metadata reading/writing
upnpserver: add support for tvshows (object.container.album.videoAlbum) and musicvideos (object.item.videoItem.musicVideoClip) and get more details if asked for it
upnp: add IMediaImporter implementation for UPnP items
media: add IMediaImportHandler implementations for movies, tvshows, episodes and musicvideos
video library: allow opening the info dialog for imported media items
filesystem: add CImportDirectory for import:// paths
videolibrary: add "Imports" nodes
[win32] update VS project files
win32: allow to run mulitple xbmc instances
WIP: plugin integration
WIP: JsonRpcImporter