parse pid printed when backgrounding a process
print useful output for tests upon failure
clean up logic for backgrounded processes
Merge pull request #365 from cdburkard/devel/test_output

print useful output for tests upon failure
Merge pull request #364 from cdburkard/patches/testCPULimit

Fix output of backgrounded processes
chdir() to correct path after calling chroot()

Since chroot() doesn't chdir() by default, we are left in
an unreachable directory in node.pexec() (and in xterms.)

fixes #370
use cgroups to calculate percentage of cpu used
Accept 'ISO' or 'boot' in file *.iso command output

Fixes #372
qcow2size(): use qemu-image instead of file

file no longer returns image size on 14.04
fixes #373
Merge pull request #369 from cdburkard/patches/hifi_multicore

Fix runCpuLimitTest with multiple cores
add Ryu controller to mininet