MachineIndexTest
core: MachineIndex updates existing entry if name, provider, path match
core: add global-status tests
core: MachineIndex more aggressively reloads data
MachineIndex lock is a monitor to allow recursion
commands/global-status: add --prune flag
core: MachineIndex keeps track of Vagrantfile name
core: Use the MachineIndex#vagrant_env method
core: MachineIndex#vagrant_env should silence warnings
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