Handy script to get time difference in Javascript

When I was writing my fabricator.js library, I had to write some unit tests where I was thinking about measuring the time between two-time points. It's a quite easy task, but when it comes to calculating every time in your mind and convert from milliseconds to seconds and then to minutes/hours etc. it's getting boring and frustrating sometimes. That's why i made a small gist that already has all this methods in time convertation and i thought that it could be helpful for other people as well :) So, here you guys :