$calendar object data array property

I needed to pass a data array to the AJAX "alter" operation in hook_calendar_block. The following patch contains 3 lines of code (1 in calendar_block.js, 2 in calendar_block.module) to support this. Example:

/**
 * Implementation of hook_calendar_block().
 */
function custom_calendar_block(&$calendar, &$date, $op) {
  switch ($op) {
    case 'load':
      $calendar->data = array('foo' => 'bar');
      break;
    case 'alter':
      // data array property contains additional attributes
      $calendar->data['foo'];
      break;
  }
}