EditHandler::getRecordEditingFields() and EditHandler::filterRecordEditingFields() are both private?

[mlewis-everley]

I am not sure if this is intentional, but in trying to overcome #195 I thought I could just extend EditHandler and overwrite getRecordEditingFields to make changes.

But as this is a private method, I end up having to duplicate almost the entire class to add three lines of code.

Do you mind if I submit a PR to change these to protected @colymba ? Or is there a reason they are private?