Jackson support

I'd like to have a way to

• produce JSON in "natural" format, i.e. { firstName: 'Donald', lastName: 'Duck'}

  instead of the Jettison mapped format { character:

  Unknown macro: { firstName}

  }

• produce JSON without taking the detour via JAXB/XML

Both can be done easily by including Jackson support.
In fact currently it is sufficient to put the three jackson jars on the classpath, but still it would be nice to have the option out of the box.

I am not sure how to specify which provider to use for "application/json" (Jackson vs. the current jaxb/json provider).