Improved precision when converting dates to UTC

Currently, the code looses to the millisecond level precision when dates are converted to UTC. This causes problems if we're trying to access the video on a per-frame basis since we can't reliably seek to time values like 4.545 seconds etc. The time difference between two frames in a 23.976 fps video comes down to about 4.17 milliseconds, and the API actually allows us to seek to that value using ```API.seekTime()``` but once we read back the value using ```API.currentTime```, it looses the millisecond level precision.