I don't like that the default refresh interval of 60 seconds is now opaque.
If we're going to include `meta_refresh_tag` then, I think the haml must pass the default delay as a parameter. Something like
```ruby
meta_refresh_tag :default_delay => 60
```

I'm still not convinced that it's a good idea (I'm not saying it isn't a good idea, only that I'm not yet convinced), but if it is, we'll need spec tests for `meta_refresh_tag`.