Ignore Drupal Cron Hook and Only Use Elysia Cron Hook

Issue Summary

Elysia Cron has proven to be valuable for our custom modules. The ability to choose when cron tasks are run has been a big deal for our development. Although the method used by Elysia Cron to take over the drupal cron process has been a stumbling block for our site. While I would like to manage other modules with Elysia Cron, something always comes up and it causes problems. We would like to continue to use the module but only our hooks that implement cronapi.

I have attached a patch that adds an option to the settings page. The option allows an administrator to ignore all the Drupal hook cron functions. This way the Drupal cron process remains unchanged and yet still process the cronapi hook as it would normally.

Does this look like a feature that could be included into this module?