Remove GC.Collect() calls and replace by only one (see comment)

Vocaluxe/Base/CSongs.cs

@@ -374,7 +374,6 @@ namespace Vocaluxe.Base
                 CLog.StopBenchmark("Load Covers/Notes");
             }
             CLog.StopBenchmark("Load Songs ");
-            GC.Collect();
         }
 
         public static void LoadCover()
@@ -419,7 +418,6 @@ namespace Vocaluxe.Base
                 song.LoadSmallCover();
                 NumSongsWithCoverLoaded++;
             }
-            GC.Collect();
             _CoverLoaded = true;
             CDataBase.CommitCovers();
         }

Vocaluxe/Program.cs

@@ -230,6 +230,9 @@ namespace Vocaluxe
                 CLog.StopBenchmark("Init Party Modes");
 
                 Application.DoEvents();
+                //Only reasonable point to call GC.Collect() because initialization may cause lots of garbage
+                //Rely on GC doing its job afterwards and call Dispose methods where appropriate
+                GC.Collect();
             }
             catch (Exception e)
             {

Vocaluxe/Screens/CScreenSing.cs

@@ -577,7 +577,6 @@ namespace Vocaluxe.Screens
             _Texts[_TextSongName].Text = String.Empty;
             _Texts[_TextDuetName1].Text = String.Empty;
             _Texts[_TextDuetName2].Text = String.Empty;
-            GC.Collect();
         }
 
         private void _LoadNextSong()
@@ -639,7 +638,6 @@ namespace Vocaluxe.Screens
                 _SlideShow = GetNewBackground();
                 foreach (string bgFile in song.BackgroundFileNames)
                     _SlideShow.AddSlideShowTexture(Path.Combine(song.Folder, bgFile));
-                _Background = null;
             }
             else if (song.BackgroundFileNames.Count == 1)
             {