Add European Portuguese Translation
Merge pull request #1273 from pedrosmmoreira/pm-add_european_portuguese_translation

Add European Portuguese Translation
Add support for custom Paperclip mappings

Paperclip supports custom interpolations in images' paths. In order to
ease transition into CarrierWave, support the same functionality with the
`Paperclip::Compatibility` module.

The public api is similar to Paperclip's

```ruby
class CustomUploader < CarrierWave::Uploader::Base
  include CarrierWave::Compatibility::Paperclip

  interpolate :some_method do |custom, style|
    custom.model.some_method
  end
end
```

This is accomplished by appending the desired functionality into
`CarrierWave::Compatibility::Paperclip#mappings`