Add a mode for digital time display

[walmik]

Add a digital mode for displaying time, like this

1. 00:34
2. 00:09:23
3. 01:01:50:30

[yeruizhi]

This functionality is very helpful. Has it been done? Thanks.

[yeruizhi]

I read your code and find that function. I add another formatting function that output time in fixed "hh:mm:ss" format, like "00:00:01" .

[walmik]

This functionality has not been implemented as yet. Please do feel free to submit a PR in case you do implement it :)

[walmik]

Closing this issue in favor of issue #36