libmemif: refactor examples

- icmp_responder: responds to ICMPv4 and ARP requests
- loopback: connects two interfaces and sends a
  verification packet from master memif to slave memif
  where it is looped back
- loopback (reverse path): reverses direction of packet
  in loopback application (slave memif to master memif)

Type: refactor

Signed-off-by: Jakub Grajciar <jgrajcia@cisco.com>
Change-Id: Ie90aaa3367269408efb6c5d538ad5aa827432238
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>
diff --git a/docs/conf.py b/docs/conf.py
index ed4de0e..26ccb3f 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -21,7 +21,7 @@
 # -- Project information -----------------------------------------------------
 
 project = u'The Vector Packet Processor'
-copyright = u'2018-2021, Linux Foundation'
+copyright = u'2018-2022, Linux Foundation'
 author = u'FD.io VPP Community'
 
 # The short X.Y version