Added custom time formatter callback

[nabiulin]

No description provided.

[nabiulin]

Hi. Faced with time format issue for long recordings.
Default time format is "minutes:seconds" and it is a little bit hard to find out the original time value.
Added time format callback for such situations.
Could you please take a look?

[katspaugh]

Thanks! 👍

[nabiulin]

Cool.Thx)Could you also rebuild minified version and update the library on bower?

[katspaugh]

I did.

[nabiulin]

Thanks a lot!