Auto-insert Bootstrap 3's clearfix for differnt viewport sizes.

<?php 
/**
 * Bootstrap auto clearfix from inside loops.
 * Put this function at the start of the loop before other bootstrap cols are called.
 *
 * @param       int   $i The count from within the loop where the function is called. Starting with 0.
 * @param       array $args ['xs'=> 12, 'sm' => 6, 'md' => 4, 'lg' => 3]