fallback for custom deserializers and serializers

[amoscatelli]

No description provided.

[amoscatelli]

#172

[amoscatelli]

@Neos3452 it was harder than I imagined
Anyway I did exactly what you asked

I hope you'll merge the pull request soon

Thank you

[Neos3452]

Thanks a lot. I think this will be very valuable addition to the library. I just left a couple technical comments, the only major thing is to keep the custom serialisation callbacks compatible with the existing version. One more thing, do you think you could add a short note about this feature to the readme in the "serializer and deserializer" section? That would really make this shine.

When you make the adjustments, I will release a rc version so you can already use it in your project.

[amoscatelli]

@Neos3452 I made the change you requested. Also I provided a short description for fallback functionality and an example.

Hoping to get the RC soon.

Thank you.

[Neos3452]

Great work! Thanks a lot for this. You can try your changes with version 1.8.0-rc1