Added possibility to define minion and master configuration files variab...

Added possibility to define minion and master configuration variables during deployment from Vagrantfile. For example if you want to deploy master and minion on separate nodes you can define minion.erb template where master variable is defined like 

```
master: <%= template_values['master'] %>
```

and in Vagrantfile you can write something like this

```
config.vm.provision :salt do |salt|
     salt.minion_config = "salt/minion.erb"
     salt.template_values = {
       "master" => "a.b.c.d"
     }
```