Move nschroot main into a directory.
fix path to local package
Add skeleton of cgroups support + utils file.
Add helpers for reading/writing virtual filesystems.

This is for IO on /proc, /sys, and (especially) /sys/fs/cgroup/*.
Add a stub, Path(), use better ioutil.TempDir()
Add some more placeholders & docs.
WIP: add test, fill in a bit more, use Vfs

Not much to see here yet. Just checking in at the end of the day
and for the first time, there is a test and it passes, so that's
worth a commit.
Add a 'contain' stub.

It just has flag parsing until the cgroup module is working.
update .gitignore
Add status update to README.