Added destroy method

[kycook]

I added a destroy method to clean up memory references and event handlers and prevent the plugin from hanging around in memory after the data table is destroyed.

[DataTables]

This looks excellent - thank you for the pull request.

The only thing I would say, is that the 'destroy' event listener should be bound to DataTables using the _fnCallbackReg method: https://github.com/DataTables/DataTables/blob/master/media/src/core/core.support.js#L217 . That can be accessed via oApi._fnCallbackReg .

There are examples of how it can be used here: https://github.com/DataTables/DataTables/blob/master/media/src/core/core.constructor.js#L130 .

[kycook]

Thanks! I added a commit that changes how the destroy event listener is bound.