Task 3125: buggy mentions

Task: https://edgeryders.eu/task-3125
 * Using "features_override" module to override drupal-commons features.
 * New token "name-raw-no-spaces" to be used as the default realname pattern to store names without spaces, in order to be correctly handled by ckeditor_mentions
 * Changed realname_pattern to use "[user:name-raw-no-spaces]" pattern

Enabling this features cause a truncate of the realname table, that will be rebuilt automatically when username get printed.