Add execution datetime when printing test results

[lowlydba]

This would be some useful (and easy) data to append to the results chart after running so that external timestamps (from a build server, for example) wouldn't be required to timestamp a given result set.

I'd be happy to work on adding this feature.

[mbt1]

Happy new year, @lowlydba. Do you still want to implement this?

[lowlydba]

This is a much lower priority for me at this point, so I'm OK with closing if it isn't a popular request. Thanks for checking in!