Add IDatabase GetScalar extension method
GetScalar -> AlbumArtist
GetScalar -> Album
GetScalar -> Art
GetScalar -> Artist
GetScalar -> Favorite
GetScalar -> Folder
GetScalar -> Genre
GetScalar -> Item
GetScalar -> MediaItem
GetScalar -> MusicBrainzCheckDate
GetScalar -> Playlist
GetScalar -> Song
GetScalar -> Video
Add album artists count to status metrics
Merge pull request #188 from mdlayher/master

Add IDatabase GetScalar extension method