Update of PngComponents to 87a981f (2016-04-22)

- fixed warning (already fixed in our code by 56d13f8 - Updates needed after upgrading PngComponents)
- Packages for Berlin added. Adjusted DCU path.  (no change on the part of the code we are using)

Source commit: 376e62afa702e06ac436fc355550cb700be3b69d

source/packages/png/PngFunctions.pas

@@ -216,7 +216,6 @@ var
     BitsSize: Integer;
     bmpDC: HDC;
     bmpHandle: HBITMAP;
-    scanlineLength: Integer;
   begin
     BitsSize := 4 * SourceColor.Width * SourceColor.Height;
     Bits := AllocMem(BitsSize);