add nesting support row

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
add non-root user and thread-safe api rows

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
remove environmentfile=yes from native lxc

I could be wrong, but afaik it's not supported.

(trivial to add however.  if we deem it safe)

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Merge pull request #1 from hallyn/master

add nesting support, thread-safe api, and non-root user, and set env-file=no for lxc