Elapsed Timer (print elapsed time)

A smarter version of the built-in functions tic and toc, made for iterative/loop computations.

Using it is just as simple:
etimer = elapsedtimer;

(then after each step)
steptimer(etimer);

After each step, prints out something like:

Elapsed time: 00:01:54 Time per step: 00:00:10 Time remaining: 00:00:25

To display time remaining, it needs to know the number of steps in the computation.
You can also set it to only print out every nth step, for example every 1000 steps.