add base box info in README.
add base box info in README.

prasincs/vagrant-mesos,hippolin/vagrant-mesos,mesosphere/vagrant-mesos,afrantisak/vagrant-mesos,emccode/vagrant,emccode/vagrant,yoeluk/vagrant-mesos,yoeluk/vagrant-mesos,everpeace/vagrant-mesos,afrantisak/vagrant-mesos,mesosphere/vagrant-mesos,afrantisak/vagrant-mesos,scorpionis/vagrant-mesos,jonasrosland/vagrant-mesos,yoeluk/vagrant-mesos,scorpionis/vagrant-mesos,hippolin/vagrant-mesos,dchesterman/vagrant-mesos,codedellemc/vagrant,dchesterman/vagrant-mesos,hippolin/vagrant-mesos,cgvarela/vagrant-mesos,jonasrosland/vagrant-mesos,scorpionis/vagrant-mesos,codedellemc/vagrant,emccode/vagrant,fonhorst/vagrant-mesos,dchesterman/vagrant-mesos,fonhorst/vagrant-mesos,everpeace/vagrant-mesos,cgvarela/vagrant-mesos,fonhorst/vagrant-mesos,jonasrosland/vagrant-mesos,prasincs/vagrant-mesos,prasincs/vagrant-mesos,mesosphere/vagrant-mesos,everpeace/vagrant-mesos,cgvarela/vagrant-mesos,codedellemc/vagrant