Release Name: 0.3.3

Notes:
* License changed to Artistic 2.0
* ChangeJournalError now ChangeJournal::Error


Changes:
* Changed license to Artistic 2.0.
* ChangeJournalStruct objects are now frozen. This is read-only data.
* ChangeJournalError is now ChangeJournal::Error.
* Added test-unit 2.x as a development dependency.
* Renamed the test and example files.
* Some updates to the Rakefile and gemspec.