Smarty performance improvements

Not massively sure how much of a performance issue this improves, but we noticed Smarty compile functions hit site performance massively every now and then, so we looked into how to improve it.

Basically:

var $compile_check = false;

on line 105 of /civicrm/packages/Smarty.class.php

should be changed from 'true'.

If you think this is a good idea, I have two further improvements, one is setting this as a value in civicrm.settings.php instead so people can switch compiling on and off in development.

Finally, a way is needed to clear the compile dir, I have a Drupal module for this and again if you feel this is a worthwhile addition I will refactor to CiviCRM native.

Again, sponsored by The Monthly / Schwartz Media