improve playlist updating

the case when sizes of mpd's and ncmpcpp's are equal is redundant.
what is more, it caused unneded overhead, because it was comparing
whole playlists. plchanges commands returns only songs that have
really changed, so this piece of code was simply wrong.

src/status.cpp

@@ -190,54 +190,38 @@ void NcmpcppStatusChanged(Connection *Mpd, StatusChanges changed, void *)
 			myPlaylist->Main()->ShowAll();
 			SongList list;
 			size_t playlist_length = Mpd->GetPlaylistLength();
-			if (playlist_length != myPlaylist->Main()->Size())
+			
+			if (playlist_length < myPlaylist->Main()->Size())
 			{
-				if (playlist_length < myPlaylist->Main()->Size())
+				myPlaylist->Main()->Clear(playlist_length < myPlaylist->Main()->GetHeight() && myScreen == myPlaylist);
+				Mpd->GetPlaylistChanges(-1, list);
+			}
+			else
+				Mpd->GetPlaylistChanges(Mpd->GetOldPlaylistID(), list);
+			
+			myPlaylist->Main()->Reserve(playlist_length);
+			for (SongList::const_iterator it = list.begin(); it != list.end(); it++)
+			{
+				int pos = (*it)->GetPosition();
+				if (pos < int(myPlaylist->Main()->Size()))
 				{
-					myPlaylist->Main()->Clear(playlist_length < myPlaylist->Main()->GetHeight() && myScreen == myPlaylist);
-					Mpd->GetPlaylistChanges(-1, list);
+					// if song's already in playlist, replace it with a new one
+					myPlaylist->Main()->at(pos) = **it;
 				}
 				else
-					Mpd->GetPlaylistChanges(Mpd->GetOldPlaylistID(), list);
-				
-				myPlaylist->Main()->Reserve(playlist_length);
-				for (SongList::const_iterator it = list.begin(); it != list.end(); it++)
 				{
-					int pos = (*it)->GetPosition();
-					if (pos < int(myPlaylist->Main()->Size()))
-					{
-						 // if song's already in playlist, replace it with a new one
-						myPlaylist->Main()->at(pos) = **it;
-					}
-					else
-					{
-						// otherwise just add it to playlist
-						myPlaylist->Main()->AddOption(**it, myPlaylist->NowPlaying == pos);
-					}
-					myPlaylist->Main()->at(pos).CopyPtr(0);
-					(*it)->NullMe();
-				}
-				
-				if (myScreen == myPlaylist)
-				{
-					if (!playlist_length || myPlaylist->Main()->Size() < myPlaylist->Main()->GetHeight())
-						myPlaylist->Main()->Window::Clear();
-					myPlaylist->Main()->Refresh();
+					// otherwise just add it to playlist
+					myPlaylist->Main()->AddOption(**it, myPlaylist->NowPlaying == pos);
 				}
+				myPlaylist->Main()->at(pos).CopyPtr(0);
+				(*it)->NullMe();
 			}
-			else
+			
+			if (myScreen == myPlaylist)
 			{
-				Mpd->GetPlaylistChanges(-1, list);
-				
-				for (size_t i = 0; i < myPlaylist->Main()->Size(); i++)
-				{
-					if (*list[i] != myPlaylist->Main()->at(i))
-					{
-						myPlaylist->Main()->at(i) = *list[i];
-						myPlaylist->Main()->at(i).CopyPtr(0);
-						list[i]->NullMe();
-					}
-				}
+				if (!playlist_length || myPlaylist->Main()->Size() < myPlaylist->Main()->GetHeight())
+					myPlaylist->Main()->Window::Clear();
+				myPlaylist->Main()->Refresh();
 			}
 			if (was_filtered)
 				myPlaylist->ApplyFilter(myPlaylist->Main()->GetFilter());