Implemented base serializer functionality and factory method.
Added ability for a serializer to define alternate media types it serializes, eg. html, xhtml.
Added #attributes method on link to simplify generating metadata links for different media types.
Fixed use of name vs. id for mapping transitions.
Added method to indicate transitions that are templated.
Fix order dependency in spec.
Added interface to directly serialize Representor instances.
Updated interfaces of descriptors to support serialization.
Added missing specs for coverage
added missing documentation
Merge pull request #21 from mdsol/feature/representor_serialization

Feature/representor serialization