JsonMappingException should override getProcessor

[nickbabcock]

Currently all JsonMappingException will return null for getProcessor because it does not override the method, even though it has it's own field (_processor). Is this intended?

[cowtowncoder]

@nickbabcock probably not (I'd have to look to verify but can't think why it would be).

[cowtowncoder]

Ok I see the problem. Will fix, see if other subtypes have the same problem.