Fix 1.8 DSL#name bug.

As mentioned in issue #28, the DSL usage breaks in 1.8, so in order to get minitest-spec-rails and others working for 1.8 using the DSL module, we need a working #name method that does not return `"dunno"`. This code illustrates how `alias` will not work in 1.8 for #name while the pull request works around this 1.8 oddity.

```ruby
module DSL
  def to_s
    super
  end
  alias :name :to_s
end

class Bar
  extend DSL
end

puts Bar.to_s
puts Bar.name # dsl_fail.rb:3:in `name': super: no superclass method `to_s' for Bar:Class (NoMethodError)
              # from dsl_fail.rb:13
```