update doc to not use the root zone for everything (#3288)

Update all documentation in the tree to use example.org as an example
configuration (in so far possible). As to get out of the just use "."
and fallthrough and things would be fine.

Signed-off-by: Miek Gieben <miek@miek.nl>

plugin/etcd/README.md

@@ -77,15 +77,19 @@ This causes two lookups from CoreDNS to etcdv3 in certain cases.
 This is the default SkyDNS setup, with everything specified in full:
 
 ~~~ corefile
-. {
-    etcd skydns.local {
+skydns.local {
+    etcd {
         path /skydns
         endpoint http://localhost:2379
     }
     prometheus
-    cache 160 skydns.local
+    cache
     loadbalance
+}
+
+. {
     forward . 8.8.8.8:53 8.8.4.4:53
+    cache
 }
 ~~~
 
@@ -93,12 +97,16 @@ Or a setup where we use `/etc/resolv.conf` as the basis for the proxy and the up
 when resolving external pointing CNAMEs.
 
 ~~~ corefile
-. {
-    etcd skydns.local {
+skydns.local {
+    etcd {
         path /skydns
     }
-    cache 160 skydns.local
+    cache
+}
+
+. {
     forward . /etc/resolv.conf
+    cache
 }
 ~~~