#801 Updated status of HTML5 features to 'rec' in features-json files...

Also, changed the `menu` element to `wd` to reflect that it is part of 5.1. Made a few minor changes to descriptions, mostly involving adding periods at end for consistency.

Please note that I did *not* change any of the URLs that point to the specs. Please see my question in #801 about whether they should be updated to point to the W3C Recommendation instead of WHATWG.

Thanks for providing caniuse to the community. Hope this update helps some.