Simple function call generator with time measurment.

Usage:

Call 100x

timer:sleep(3).

1> fcg:run(timer,sleep,[3], 100). calls: 100, tot:400214 uSec, call: 4002.14 uSec

Call the same, but in 5 threads (processes)

2> fcg:prun(timer,sleep,[3], 100, 5). calls: 100, tot:396813 uSec, call: 3968.13 uSec run tinme: 79396

Reported times are in microseconds.