Configurable wait for machine to be ready

[gabriel-v]

The user should be able to configure the amount of time Vagrant will wait for a VM to be ready, here:

vagrant-vmck/lib/vagrant-vmck/action/create.rb

Line 22 in 340e280

retryable(:tries => 120, :sleep => 1) do

I think we will need to set this up to a few hours.