UIkit incompatible with Field Group

The theme applies UIkit's vertical accordions indiscriminately to any kind of fieldset__collapsible:

// preprocess.inc, line 716
function uikit_preprocess_fieldset(&$variables) {
  [..]
  if ($group_fieldset) {
    $variables['theme_hook_suggestions'][] = 'fieldset__grouped';
  }
  elseif ($collapsible) {
    $variables['theme_hook_suggestions'][] = 'fieldset__collapsible';
    $variables['element']['#attributes']['class'][] = 'uk-margin';
    $variables['element']['#attributes']['class'][] = 'uk-accordion';
    [...]
  }
}

dsdfdf
Field group gives use a variety of options, that we could render as beautiful UIKit components.
The UIkit components module does no deal with this.
We should make a condition to deal with those:

• Fieldsets as .uk-fieldset, see docs (already there)
• Accordions (already there)
• Tabs as .uk-tab
• Vertical tabs as .uk-tabs.uk-tab-left