Revision history for Sub-Exporter

        break out Data::OptList for future disting
        remove an "optimization" that broke expand_opt_list
        improve detection of group generators
        improve data passed to hooks (if you relied on the guts, you'll break)
        the ::Util module

0.93    2006-03-26
        internal refactoring
        add more arguments to collector hook calls

0.92    2006-03-16
        FIX BUG in nested imports: when importing groups A and B, and group B
        includes group A, the nested group would be ignored, even though it was
        not recursing

        allow 'into_level' parameter to setup_exporter
        rewrite collection collector to be more efficient
        rewrite opt list handlers to be more efficient
        restate some code to improve clarity and coverage (now 100%)
        better diagnostic messages

0.91    2006-03-16
        added "import elsewhere" option to generated exporter (thanks chansen!)

0.90    2006-03-11
        first public release