Fix assignment
Return nil if container has no init
No setter syntax for methods taking two arguments
Deal with possible array values
Fix handling of LXC::Container#start argument
Fix lxc_attach argument parsing
Fix lxc_attach payload argument
Define constants in LXC, not in LXC::Container
Implement LXC::run_command
Fix IO object test
Fix LXC::run_command argument count
Adding unit tests