Added tests for buffered streams.

Made wxBufferedOutputStream call Sync() in
    the destructor and SeekO().
  Documented this.
  Use buffered streams in wxImage. Seems to
    significantly speed-up the sample.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4847 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/stream.cpp

@@ -856,6 +856,7 @@ wxBufferedOutputStream::wxBufferedOutputStream(wxOutputStream& s)
 
 wxBufferedOutputStream::~wxBufferedOutputStream()
 {
+  Sync();
   delete m_o_streambuf;
 }
 
@@ -868,6 +869,7 @@ wxOutputStream& wxBufferedOutputStream::Write(const void *buffer, size_t size)
 
 off_t wxBufferedOutputStream::SeekO(off_t pos, wxSeekMode mode)
 {
+  Sync();
   return m_o_streambuf->Seek(pos, mode);
 }