multithreading

After the chefserver, controller1 and controller2 nodes are up, all other nodes are built simultaneously.  This results in a build that runs approximately ten minutes shorter.

2687.31s
total: 45m => 35.3m
in build: 38.5m => 28.2m

total: 2687s => 2118; 21% improvement 
in build: 2310s => 1692; 27% improvement