Display the video title - add title attribute

[jakeparis]

This PR adds a title attribute so the pre-clicked element displays a title. The title's style is basically the same as YouTube's.

[paulirish]

i think this is a bit overstyled. i want the CSS & JS to be as small as reasonably possible, so i'd like to only include these if totally necessary. Can you whittle these down a bit?

[jakeparis]

Removed extraneous things, and moved styles to ::before element. Also, I changed the background from a base64 encoded svg into a linear-gradient, because the svg isn't stretching correctly when title text expands the element.

[paulirish]

Thank you jake! appreciate the fine work here.

[paulirish]

@jakeparis i notice now...

That you took the element's title attribute value and then move it to data-title. But.. we could drop that line of JS and instead ask the developer to provide a data-title attribute. Do you (or anyone else) have a preference?

(Also I now see some overlap with the intention of playLabel and this title, but the current treatment seems to be OK)

Lastly, I know you did this YEARS ago so if you totally forget.. no worries. <3