Cloud Manufactory Heartbeat Control

Allows you to fine-tune the WordPress Heartbeat API frequency and behavior:
* Pause the Heartbeat API (useful for debugging).
* Decrease Heartbeat API frequency (useful when having performance issues on the site).
* Automatically decreases the frequency when the site is having performance issues (useful for mitigating attacks).
* Automatically decreases the frequency when the last heartbeat ajax call failed (useful for helping the server bounce back).
* Allows you to manually control the frequency.