Upgraded to Validator 1.2 with HTML5 Validation

The 1.2 release of the W3C Markup Validator is an enhancement and bug fix release. For details, see the 1.2 announcement.

With the addition of the validator-nu sub-system, HTML5 is (finally!) supported. Note: currently, HTML5 validation is slow (8+ sec) -- this will be fixed in future releases.