added ping

client

@@ -52,6 +52,10 @@ while true do
                     end
                 end
             end
+        elseif type(data) == 'string' then
+            if data == 'ping' then
+                rednet.send(master, "Pong!")
+            end
         end
     end
 end

control

@@ -73,6 +73,8 @@ function control()
         -- print(dump(input))
         if input[1] == 'lookup' then
             print(rednet.lookup("rmm", input[2]))
+        elseif input[1] == 'ping' then
+            rednet.send(tonumber(input[2]), 'ping')
         elseif input[1] == 'eval' then
             rednet.send(tonumber(input[2]), {"eval", input[3]})
         elseif input[1] == 'move' then