Add annotation to allow defining order of property serialization (@JsonPropertyOrder?)

JAXB has annotation @XmlAccessorOrder which allows specifying order in which child elements are to be serialized.
It would be useful to be able to allow the same with Json (although not quite as necessary, since Object properties are defined to be logically unordered). This could be achieved by adding a simple new annotation which would be used for (re)ordering property serializers for generic BeanSerializer.

Also: if and when this is implemented, should ensure that JAXB definition is discovered by JAXB annotation introspector.