1.6.0-DEVELOP

Add files via upload

1.2.0-DEVELOP

Changelog:

• Item's persistent data can now be accessed through the API.
• AbstractPersistentData was rewritten.
• Custom write/delete events were added

In addtion to the first release - Quick bug fix

Apparently, when using the unregisterData(); method with AbstractPersistentData, nothing was happening. This bug was fixed