Permit the timeout period for a fetch call to be set via an optional :ti...

...meout parameter

This addresses some issues we run into occasionally where caches are shut down during a redeployment but live threads still reference them and then lock for 45 seconds waiting for the caches.  Permitting this wait to be configurable is a nice to have that we monkey-patched into our TorqueBox.  Thought it might be useful to the community so added this pull request.