Webserver: GetAllSongs() uses now a cache

Vocaluxe/Base/Server/CVocaluxeServer.cs

@@ -624,11 +624,18 @@ namespace Vocaluxe.Base.Server
             return _GetSongInfo(song, true);
         }
 
+
+        private static SSongInfo[] songInfoCache = null;
         public static SSongInfo[] GetAllSongs()
         {
-            List<CSong> songs = CSongs.Songs;
-            return (from s in songs
+            if (songInfoCache == null)
+            {
+                List<CSong> songs = CSongs.Songs;
+                songInfoCache = (from s in songs
                     select _GetSongInfo(s, false)).AsParallel().ToArray<SSongInfo>();
+            }
+            
+            return songInfoCache;
         }
 
         public static string GetMp3Path(int songId)