D7 function to revert all features.

gistfile1.php

function foo_features_revert_all($force = FALSE) {
  module_load_include('inc', 'features', 'features.export');
  $features_to_revert = array();
  foreach (features_get_features(NULL, TRUE) as $module) {
    if ($module->status) {
      // If forced, add module regardless of status.
      if ($force) {
        $features_to_revert[] = $module->name;
      }
      else {
        switch (features_get_storage($module->name)) {
          case FEATURES_OVERRIDDEN:
          case FEATURES_NEEDS_REVIEW:
          case FEATURES_REBUILDABLE:
            $features_to_revert[] = $module->name;
            break;
        }
      }
    }
  }

  if ($features_to_revert) {
    foreach ($features_to_revert as $module) {
      if (($feature = features_load_feature($module, TRUE)) && module_exists($module)) {
        $components = array();
        // Forcefully revert all components of a feature.
        if ($force) {
          foreach (array_keys($feature->info['features']) as $component) {
            if (features_hook($component, 'features_revert')) {
              $components[] = $component;
            }
          }
        }
        // Only revert components that are detected to be Overridden/Needs review/rebuildable.
        else {
          $states = features_get_component_states(array($feature->name), FALSE);
          foreach ($states[$feature->name] as $component => $state) {
            if (in_array($state, array(FEATURES_OVERRIDDEN, FEATURES_NEEDS_REVIEW, FEATURES_REBUILDABLE)) && features_hook($component, 'features_revert')) {
              $components[] = $component;
            }
          }
        }

        if (!empty($components)) {
          foreach ($components as $component) {
              features_revert(array($module => array($component)));
          }
        }
      }
    }
  }
}