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/generic/grideditors.h

@@ -210,7 +210,7 @@ public:
         { return new wxGridCellFloatEditor(m_width, m_precision); }
 
     // parameters string format is "width[,precision[,format]]"
-    // format to choose beween f|e|g|E|G (f is used by default)
+    // format to choose between f|e|g|E|G (f is used by default)
     virtual void SetParameters(const wxString& params) wxOVERRIDE;
 
 protected: