This is a TODO file for only this branch (config-overhaul)

* Config validation
* Separation of global vs VM configuration.
* Finish Config::Container
* Have Vagrant::Environment use new global config, put VM-specific
  config directly into Vagrant::VM objects
* Only allow one kind of vagrantfile to be loaded (i.e. if both
  Vagrantfile and vagrantfile exist, throw an error)
* Nicer error if can't setup home directory