nfd-status: Define format and implement --xml option

The ether URI format "ether://01:00:5e:00:17:aa" violates
the URI specification, so it has been changed to
ether://[01:00:5e:00:17:aa] in this commit.

refs: #1438

Change-Id: I1218374b75f919a5e1ab158bbab2e217e64aced3
diff --git a/docs/manpages.rst b/docs/manpages.rst
index 3b8a496..6a52897 100644
--- a/docs/manpages.rst
+++ b/docs/manpages.rst
@@ -8,6 +8,7 @@
    manpages/nrd
    manpages/nfdc
    manpages/nfd-status
+   schema
    manpages/nfd-status-http-server
    manpages/ndn-autoconfig
    manpages/ndn-autoconfig-server