various fixes (#70)

- dont show ccr status if license insufficient
- add automated tests
- fix config loading
- fix search output
- fix `license show` panics
- fix `ilm show` completion
- print ask passwd prompt to stderr

t/cluster.yaml

@@ -0,0 +1,7 @@
+# esctl config
+clusters:
+    docker/domdoc:
+        uri: https://elastic:9200
+        user: elastic
+        token: ""
+        default: false