* Documentation is pretty sketchy.
* More test cases.
* AUTOLOADed get methods:
        - document them better
                + can auto-generate much docs using ->format_signature 
        - ensure they can be called as get_X and get_Y where X is the microformat
          class/rel name, and Y is the hash key from ->data which sometimes differ.
                + make sure any such differences are clearly documented
* Microformats 2.0???
* Drop dependencies on CGI/CGI::Util and URI::URL.