pingserver: change the short form of --freshness to -f

-x is still accepted but will print a deprecation warning

Change-Id: Ibc2e9750006a450c85d19c432ec1a02416cdc174
diff --git a/manpages/ndnpingserver.rst b/manpages/ndnpingserver.rst
index da948d1..f3efeb9 100644
--- a/manpages/ndnpingserver.rst
+++ b/manpages/ndnpingserver.rst
@@ -1,25 +1,23 @@
 ndnping
 =======
 
-Usage
------
+Synopsis
+--------
 
-::
-
-    ndnpingserver [-h] [-V] [-x freshness] [-p satisfy] [-t] [-s size] prefix
+**ndnpingserver** [-h] [-f *freshness*] [-p *count*] [-s *size*] [-t] [-q] [-V] *prefix*
 
 Description
 -----------
 
-``ndnpingserver`` listens for the specified Interest prefix and sends Data packets when an Interest
-under that prefix is received. Once ``ndnpingserver`` either reaches the specified total number of
-Interests to be satisfied or receives an interrupt signal, it prints the number of Data packets
-sent.
+:program:`ndnpingserver` listens for the specified Interest prefix and sends Data packets when
+an Interest under that prefix is received. Once :program:`ndnpingserver` either reaches the
+specified total number of Interests to be satisfied or receives an interrupt signal, it prints
+the number of Data packets sent.
 
-``prefix`` is interpreted as the Interest prefix to listen for. The FreshnessPeriod of Data packets
-is set with the -x option (default 1000ms). The content is by default empty, but if a size is
-specified with the '-s' option, it contains the specified number of the letter "a". Finally, the
-Data is signed with an SHA256 digest.
+*prefix* is interpreted as the Interest prefix to listen for. The FreshnessPeriod of Data packets
+is set with the **-f** option (default 1 second). The content is by default empty, but if a size
+is specified with the **-s** option, it contains the specified number of the letter "a". Finally,
+the Data is signed with a SHA-256 digest.
 
 Options
 -------
@@ -27,27 +25,28 @@
 ``-h``
   Print help and exit.
 
+``-f``
+  Set freshness period in milliseconds.
+
+``-p``
+  Maximum number of pings to satisfy. A value of 0 means no limit.
+
+``-s``
+  Size of the response payload.
+
+``-t``
+  Print a timestamp before each log message.
+
+``-q``
+  Do not print a log message each time a ping is received.
+
 ``-V``
   Print version and exit.
 
-``-x``
-  Set freshness period in milliseconds (minimum 1000ms).
+Example
+-------
 
-``-p``
-  Set maximum number of pings to satisfy.
+Listen on ``/edu/arizona`` and respond to at most 4 pings, printing the timestamp
+on each received ping::
 
-``-t``
-  Prints a timestamp with received Data and timeouts.
-
-``-s``
-  Specify the size of the response payload.
-
-Examples
---------
-
-Listen on ``ndn:/edu/arizona`` and response to at most 4 pings, printing timestamp on each received
-ping
-
-::
-
-    ndnpingserver -p 4 -t ndn:/edu/arizona
\ No newline at end of file
+    ndnpingserver -p 4 -t /edu/arizona