Result of running the 2to3 script.
Fixup import statements bent by 2to3
Improve type checking expressions.
Fixup raise expressions
Cleanup spacing.
Save prefs using binary file.
Fix row position calculations to return int values.
Add None checks to handle_motion()
Remove superfluous str.lower()
Remove broken and superfluous alphabet expression.
Fix inconsistent file extensions in load/save dialogs of sample app.
Use binary files for pickle load/dump in sample app.
Cleanup comparisons to None