Support for oneOf, implementation advice

[clouetb]

Hi there, while trying to generate using your tool (which is great by the way), I'm greeted with the same error depicted in issue #3. It appears that my swagger is containing oneOf (for inheritance implementation purpose).

I looked at the way you're implementing the allOf but it seems the way should be different in this case and I'm a little bit puzzled by the way it should be. Specifically, it seems two approaches may be chosen: either generate one form that would be somewhat polymorphic, or generate one form for each subclass type. Would you mind sharing some implementation advice to let me try to submit a PR?