Add ms precision to finished dungeon timer

[castro732]

Trying to (kind of) add the request made in #35, this adds the exact completion time as informed by the blizzard api after dungeon completion, and shows it with ms precision.

How it looks when timing a key

[happenslol]

Ohh that's a really good idea! I think we should provide an option to turn on/off millisecond display, but updating the time to the blizz provided one on completion should definitely be the default. Could you add that option somewhere? I think it belongs in the general tab, probably

[castro732]

I added the option to enable/disable the ms display, but still the timer will show the time from blizzard api upon key completion.

[happenslol]

Awesome, thank you!