Update html5-elements.vim to W3C CR 2014-02-04.

Moving canvas to Scripting, adding/removing some elements and sorting
sections in line with the spec.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Merge pull request #22 from omasanori/cr-html5-20140204

Update html5-elements.vim to W3C CR 2014-02-04.