Change label for "Rebuild Table" button

I'm surprised no one has asked for this one.

This patch adds a theme function which allows changing the label for the "Rebuild Table" button.

For example:

/**
 * Theme the label for the "Rebuild Table" button (tablefield module)
 */
function YOUR_THEME_tablefield_rebuild_table_button($field_name) {
  if ($field_name == 'MACHINE_FIELD_NAME') {
    return t('New Label');
  }
  return t('Rebuild Table');
}

Obviously replace YOUR_THEME and MACHINE_FIELD_NAME with the name of the theme you're using and the name of the tablefield field you're trying to theme the button for respectively.