Acclerate improvements

* Added capability to support multiple keys, so clients from different
  machines can connect to a single daemon instance
* Any activity on the daemon will cause the timeout to extend, so that the
  daemon must be idle for the full number of minutes before it will auto-
  shutdown
* Various other small fixes to remove some redundancy

Fixes #5171
Documentation updates for accelerate mode improvements
Adding in a configurable option for the accelerate daemon timeout

This was apparently an oversite, as it has never been configurable
despite having a module parameter for the timeout.