rails-assets 'jquery-ujs' overwrites own older 'jquery-ujs' file

Using this

``` ruby
source 'https://rails-assets.org' do
  gem 'rails-assets-jquery-ujs'
end
```

in your main app will overwrite the use of the local `jquery-ujs.js` file located in `rollout_ui/lib/rollout_ui/engine/vendor/assets/javascripts/jquery-ujs.js`. This can cause problems because the latest `jquery-ujs.j` file demands a jquery version higher then 1.8.0 
