docs: Extending documentation and manpages

Refs: #1462

Change-Id: If33a0f3c623daf3502ed301bcdc63892779463e3
diff --git a/docs/manpages/ndnsec-cert-dump.rst b/docs/manpages/ndnsec-cert-dump.rst
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+ndnsec-cert-dump
+================
+
+``ndnsec-cert-dump`` is a tool to dump a certificate from **Public Info Base** or file and output
+it to standard output.
+
+Usage
+-----
+
+::
+
+    $ ndnsec-cert-dump [-h] [-p] [-ikf] name
+
+Description
+-----------
+
+``ndnsec-cert-dump`` can read a certificate from **Public Info Base (PIB)** or a file and output
+the certificate to standard output.
+
+By default, ``name`` is interpreted as a certificate name.
+
+Options
+-------
+
+``-i``
+  Interpret ``name`` as an identity name. If specified, the certificate to dump is the default
+  certificate of the identity.
+
+``-k``
+  Interpret ``name`` as a key name. If specified, the certificate to dump is the default certificate
+  of the key.
+
+``-f``
+  Interpret ``name`` as a path to a file containing the certificate. If ``name`` is ``-``,
+  certificate will be read from standard input.
+
+``-p``
+  Print out the certificate to a human-readable format.
+
+Examples
+--------
+
+Dump a certificate from PIB to standard output:
+::
+
+    $ ndnsec-cert-dump /ndn/test/KEY/david/ksk-1396913058196/ID-CERT/%00%00%01E%3E%9D%A0%DE
+
+Dump a certificate to a human-readable format:
+::
+
+    $ ndnsec-cert-dump -p /ndn/test/KEY/david/ksk-1396913058196/ID-CERT/%00%00%01E%3E%9D%A0%DE
+    Certificate name:
+      /ndn/test/KEY/david/ksk-1396913058196/ID-CERT/%00%00%01E%3E%9D%A0%DE
+    Validity:
+      NotBefore: 20140401T000000
+      NotAfter: 20150331T235959
+    Subject Description:
+      2.5.4.41: David
+      2.5.4.10: Some Organization
+    Public key bits:
+    MIIBIDANBgkqhkiG9w0BAQEFAAOCAQ0AMIIBCAKCAQEAtLq50tpynJ15zExEh9l6
+    jvh/HOmwhOppr/hTEPYUn2VTh21+JJIg5pHAAH/DQr8Bq5BGrdDUCIShxSxbaHwu
+    a1y4XgKP1MYBQP/WzcIhIzB/3PBDdmE0jM3Qg6yuk8BOwett3C07GtwW9dfgacwt
+    aC29xIHnYKfryH/gBSIDUIb38M7ILIDgQeIiQcHGHoFO8CbDtKY2OvVkFNgxowAR
+    Xn+gtkIfMdE77Z8p0S21pYfdvPuIpVVLy7lnFdwGzyCi3nmbtd/r9NSTepBczWQz
+    zBbThT7yfeNyHWLu0PZPdz84UpNPsBad3Bx9tT31noIVnt8yyBEfEU1jyEIVkm8U
+    VQIB