Display warning to user about the VirtualBox SharedFoldersEnableSymlinksCreate
option with link to VirtualBox documentation and instructions on how the
setting can be disabled.
Prior to this commit, the virtualbox synced folder option
`SharedFoldersEnableSymlinksCreate` was always enabled. This commit
introduces a config option and an environment variable which allows
users to configure the option globally or per synced_folder in their
Vagrantfile.
It should be valid to allow paths with spaces for the synced folder
guest path but since the guest path is used to generate the ID (if one
isn't provided), this will err out in VirtualBox because it doesn't
allow spaces for the --name argument. We should simply convert ' ' to
'_' as we do with other special characters.
Initial work
commands/up: make sure all names to with_target_vms are strings
providers/docker: create a docker host VM if needed
providers/docker: executor abstraction for driver to eventually support remote
providers/docker: vagrant executor
providers/docker: support creating the machine
providers/docker: status works if host VM is gone
providers/docker: use start fence to get real docker output
core: Call preserves stack ordering
core: support Message post option
providers/docker: Guard some features with HasSSH checks
providers/docker: much better messaging around create/destroy
providers/docker: output the container ID on create
providers/docker: copy the hostmachine Vagrantfile to the data dir
providers/docker: should make host machine before any up action
providers/docker: HandleBox before the host machine
providers/virtualbox: functional_vboxsf to disable vboxsf
providers/virtualbox: synced folder usable method should take 2 args
providers/docker: default machine name to :default
