Diff and form data field types can't handle null bytes

By beginning my implementation I noticed the form_data field also uses the `serialize` method but not the `map` field type. Form data probably doesn't include class instances but following the recommendation of the PHP documentation seems like a good idea.

Hi @tgauges

Thx for a good finding. You've provided a very good solution so, I love it. Let's complete it. I will then push a new release. I've just left few comments there.

Kind regards
Andrei

I think I might need some help with the update hook. I have some experience with updating contrib fields (added via GUI), but not base fields. Do you know some guide of existing code I can take a look at?

What also should be a part of the update hook in my opinion:

• updating the view (if it exists)
• removing broken values in the database

hi @tguages

Sure, I will try to find some time and get it finished. Leave it for now if you feel you can't complete it. You did a great job. I will also need to test it properly.