Revision history for Perl extension XML::Flow.
0.86
    - add default handler '*'
0.85
    - support for nested tags into text, eg.:
        <tag> text text <tag2>some</tag2> continued text</tag>
0.84
     - tune xml size 
0.83 - fix: don't pass undefined value of text to tags handler

0.82 - add function xml2ref(), ref2xml;
     - add tests;
     - add support handlers withow embeded xml_flow_struct
0.81 - remove debug, fix pod
