Minor revisions in doc on W3C APIs
Minor revisions in doc on W3C APIs

- Some wording improvements (I hope)
- Turn W3C / MDN links from headlines into comments

Change-Id: Ia6dc6e41349cb75a98eed4d46f48f9197691056c

softnep0531/tabrisjs,pimaxdev/tabris,mkostikov/tabris-js,eclipsesource/tabris-js,mkostikov/tabris-js,pimaxdev/tabris,eclipsesource/tabris-js,softnep0531/tabrisjs,eclipsesource/tabris-js,moham3d/tabris-js,moham3d/tabris-js