Add progress tracker class to qcore

[jpa198]

Use progress tracker in IM_calc to show the status of IM calculations

[jpa198]

A bit overkill for the spec, but I basically had it lying around. And it might be useful other places.

[jpa198]

Example output each time update is called:
100.0% complete. Time taken for this block: 0.29s. Time elapsed: 3.89s. Time remaining: 0.00s. Total time: 3.89s.

[jasonmotha]

Looks good. You probably could have used some of the date/time package for your pretty_print but probably simpler without it.

I really like that you can just import it easily for quick scripts that you write too.

[sungeunbae]

Awesome