typo fixes - https://github.com/vlajos/misspell_fixer
Added persistent data handler
Updated version constraint for 4.1
Merge pull request #264 from SammyK/persistent-data-handler-interface

[4.1] Added persistent data handler
Merge pull request #265 from vlajos/typofixes-vlajos-20141107

typo fixes - https://github.com/vlajos/misspell_fixer
Merge pull request #269 from SammyK/update-version-constraint-4.1

[4.1] Updated version constraint for 4.1