Support HTML 5 tags

[pasviegas]

As HTML comes up, it would nice to have HTML 5 support.

[erikvold]

can you be specific which tags you'd like to be added, or do you have a list of all of the new HTML5 tags?

[erikvold]

http://www.quackit.com/html_5/tags/

probably don't want all of these.. maybe providing an obvious API for extending the tags supported would be a better idea.