* middleware/proxy: add spray keyword
When spray is used, the proxy will, when all backend are down, spray to
each target. When not used, default to the old defaults: max 1 failure
and no spray. These defaults are also used when forwarding queries to
another CoreDNS instance.
Update the README with the new keyword.
* typos
* Make MaxFail = 1 again
* more reversals
This implements stubzones in the same way as SkyDNS. This
also works with multiple configured domains and has tests.
Also add more configuration parameters for TLS and path prefix and
enabling stubzones. Run StubUpdates as a startup command to keep up to
date with the list in etcd.