#20 Feature request: elapsed and final time display

[Jeff Keegan]

In addition to the estimated build time that is now displayed, it would be useful to show the amount of time that has elapsed since the beginning of the print. If the user presses Pause to pause the build, maybe it then should show two elapsed time displays: total elapsed print time, and total elapsed real time.

When the build is complete, having that display show an accurate display of how long the build took would be useful as well.