Adds a time canvas for display of the time.

[manuelmitasch]

By default this feature is disabled. It can be enabled by setting the param showTime to true.

Needed this for my project. Feel free to reject it if you think it's too specific.

[katspaugh]

Hi Manuel!

I'm afraid I do think it's rather specific. Besides, we support the same functionality for both Canvas and SVG. I would gladly accept it as a plugin, though. As a side note, the drawer must not be directly using the backend. The backend and drawer both provide event interface, through which WaveSufer communicates with them to produce combined actions.

[manuelmitasch]

Thanks for the great work.
Finally figured out that it's easily doable without changing the library (due to it's open api).

[katspaugh]

Thanks to you as well!