unbound operate method signature docs.
let's ship a config file with generous retries.
Attempt to store DNS record in cache
update docs to reflect cachiness.
Revert "let's ship a config file with generous retries."

This reverts commit 6e2727c1626b76b34ceff2e5710dc18a38a2c504.
Merge branch 'caching'

Conflicts:
	unbound_ec2.py
clean up.
WIP pqueue
WIP invalidator scheduler.