Add support of well-known Microformats (hCalendar, hCard, hReview, etc) to XWiki pages

Several reasons:

• Improve searchability of XWiki sites
• Easy feature to add
• Adds a new hip feature to XWiki

See http://www.whymicroformats.com/articles/2006/10/04/introduction-to-microformats and http://microformats.org/wiki/Main_Page