Multi CPU support

Created by: myrinx

Hi,

It seems in my Debian 7 64bit environment with 2 cores that Arachni limits itself to using only 1 of the available cores, and slows down a lot once it reaches the 100% cpu mark.

Is this something i can fix myself or would it be possible to see what can be done to utlize all available resources on the system? Im' on the experimental branch.

THanks!