erlxc: export container configuration functions
typespec: list() -> proplists:proplist()
erlxc: clean up typespecs
erlxc: set lxc path at when port starts
erlxc: rename attach -> connect

liblxc has an attach(), used to run commands in the container. Rename
attach/1,2 to connect/1,2. connect/1,2 is used to access the container
system console.