Global: $swifty_lib_dir

Swifty Lib has an global to load php files only when needed.

Some php files in the lib are only used in certain circumstances. This improves load times.

Example:

global $swifty_lib_dir;
if( isset( $swifty_lib_dir ) ) {
  require_once $swifty_lib_dir . '/php/lib/swifty-image-functions.php';
}