Fix spelling in comments and documentation using codespell

Apply the utility from https://github.com/codespell-project/codespell/
to fix spelling issues in the headers under both include and interface
directories and add a file with a couple of exceptions.

The exact command line used was:

    $ codespell -w -I misc/scripts/codespell.ignore -i 3 in*

include/wx/msw/progdlg.h

@@ -64,7 +64,7 @@ private:
     // generic version does. This is done as part of DoNativeBeforeUpdate().
     void DispatchEvents();
 
-    // Updates the various timing informations for both determinate
+    // Updates the various timing information for both determinate
     // and indeterminate modes. Requires the shared object to have
     // been entered.
     void UpdateExpandedInformation(int value);