.zsh: fix docker-last() function so that it returns the last running container (and not an image id)
.vimrc: set shell option so we don't get /bin/sh when running commands from vim
.zsh: remove docker-lxc-attach() which doesn't work...
.zsh: add docker-enter() function to enter a container through the 'nsenter' command
.zsh: run docker-enter script with sudo in docker-enter() command
.zsh: complete docker-create-repo() function to create local directory under ~/Projects