Pin jquery-ui-rails to < 5.0

- due to breaking changes in asset names; need to change

jquery-ui-rails < 5.0:
```javascript
//= require jquery.ui.all
```
```css
= require jquery.ui.all
```

jquery-ui-rails >= 5.0:
```javascript
//= require jquery-ui
```
```css
= require jquery-ui
```