Applied patch for multiple file selection, documented.

Fixed some compilation warnings,
  Minor change to OpenGL code.
  Documented wxImageHandler::GetImageCount() and related.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4784 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/dataobj.cpp

@@ -204,7 +204,7 @@ size_t wxFileDataObject::GetDataSize() const
     return res + 1;
 }
 
-bool wxFileDataObject::SetData(size_t size, const void *buf)
+bool wxFileDataObject::SetData(size_t WXUNUSED(size), const void *buf)
 {
     // VZ: old format
 #if 0