add movie and show genres (#61)

* load movie genres from sidecar metadata

* search movie and tv show genres

* rebuild all playouts (needed after time zone fix)

* code cleanup

* fix duplicate tv show search results

ErsatzTV.Core/Domain/Metadata/Genre.cs

@@ -0,0 +1,8 @@
+namespace ErsatzTV.Core.Domain
+{
+    public class Genre
+    {
+        public int Id { get; set; }
+        public string Name { get; set; }
+    }
+}

ErsatzTV.Core/Domain/Metadata/Metadata.cs

@@ -15,5 +15,6 @@ namespace ErsatzTV.Core.Domain
         public DateTime DateAdded { get; set; }
         public DateTime DateUpdated { get; set; }
         public List<Artwork> Artwork { get; set; }
+        public List<Genre> Genres { get; set; }
     }
 }