Get rid of getStride()

It was confusing and not properly used everywhere.
Callers should use the stride they get when they get
the buffer pointer.
diff --git a/vncviewer/Win32PixelBuffer.cxx b/vncviewer/Win32PixelBuffer.cxx
index 429f63f..9fb0414 100644
--- a/vncviewer/Win32PixelBuffer.cxx
+++ b/vncviewer/Win32PixelBuffer.cxx
@@ -40,7 +40,7 @@
 Win32PixelBuffer::Win32PixelBuffer(int width, int height) :
   PlatformPixelBuffer(rfb::PixelFormat(32, 24, false, true,
                                        255, 255, 255, 16, 8, 0),
-                      width, height, NULL),
+                      width, height, NULL, width),
   bitmap(NULL)
 {
   BITMAPINFOHEADER bih;