Should count physical not logical cores on hyper threading CPUs

Origami Version: 0.6.9
Ubuntu 9.04

When installing the 32bit client, Origami will start up one copy for each logical core on Hyper Threading systems. While this does apparently provide a small over all speed benefit, Stanford prefers users only run one client per physical core to enable faster completion of each result, so Origami should either only count physical cores, or at least provide the user with an option to reduce the number of clients run manually.