[BUILD] Randomization script refactoring

1) Refactored randomization logic to the top
2) Add logics to support window platforms
I'd probably indent this very long block differently, to increase readability (but that is a subjective quality :)

```ruby
configuration.

  each do |k, v|
    if(v.kind_of?(Hash))
      if(v.has_key?(:method))
        randomizer = Randomizer.new(v[:choices])
        v[:selections] = randomizer.__send__(v[:method])
      end
    else
      v.each do |x|
        if(x.has_key?(:method))
          randomizer = Randomizer.new(x[:choices])
          x[:selections] = randomizer.__send__(x[:method])
        end
      end
    end
  end.

  each do |k, v|
    if(v.kind_of?(Array))
      selections = v.inject([]) do |sum, current_hash|
        sum.push(current_hash[:selections])
      end
    else
      selections = [v[:selections]] unless v[:selections].nil?
    end

    generated[k] = selections unless (selections.nil? || selections.size == 0)
  end

```

(Ruby 1.8.7 compatible.)