Support for lxc 1.0.0

Hi,

this should add basic support for lxc 1.0.0.
With 1.0.0 the following things has changed:

* `lxc-version` was removed and `lxc-info --version` has to be used
* output of `lxc-info -n foo` has changed (state => State, pid => PID)
* `lxc-ps` and `lxc-netstat` where removed, instead `lxc-attach` should be used, see [mail](https://lists.linuxcontainers.org/pipermail/lxc-devel/2014-January/007433.html)

I also some removed unnecessary dependency checks for binaries which aren't provided by upstream lxc and aren't used in this gem, like `setcap` or `setuid`

Still open: reimplement `Container.processes` method to use `lxc-attach -n foo -- ps <arguments>`

Implemented and tested on debian wheezy 7.4