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/dib.h

@@ -125,7 +125,7 @@ public:
                                    const void *bits = NULL);
 
     // create a plain DIB (not a DIB section) from a DDB, the caller is
-    // responsable for freeing it using ::GlobalFree()
+    // responsible for freeing it using ::GlobalFree()
     static HGLOBAL ConvertFromBitmap(HBITMAP hbmp);
 
     // creates a DIB from the given DDB or calculates the space needed by it: