Calculate time done based on playback speed

[joshinils 13]

Since there are official playback speed options, I think it would be better to show the time when playback finishes accurately.

Currently, the two numbers at the end of the seek-bar show time left in the current video and the time on a clock when that time has passed from now (i.e. `time_done = now() + time_remaining`).
I think it would be better to show it as `time_done = now() + time_remaining / playback_speed` such that it is closer to now when playback speed is greater than 1, and further away when speed is less than 1.

Maybe the same could be done with the time remaining in the video, but that may be confusing if that changes based on playback speed.

[joshinils 13]

There are also add-ons which allow changing playback speed to an arbitrary value, I use one for Firefox:
https://addons.mozilla.org/de/firefox/addon/videospeed/
It allows changing speed in all html5 players.

[Luke 39400]

Hi, yes it makes sense. Thanks for the feedback.