Add option to divide load averages by cpu/core/hyperthread count
For example, a 1.0 load using this option means the system is at 100%
capacity regardless of whether it is a single vcpu virtual machine or
a multi-cpu, multi-core, hyperthreading server.
Merge pull request #325 from bclarkindy/check-load-per-core

Add option in check-load.rb to divide load averages by cpu/core count