print -> info; end the horror of print vs. print()

Although we could use print() from __future__, this messes
up scripts which use examples as modules.

The simple, if not nicest for 2.7, solution is to use
info(), output() and other mininet.log functions. The disadvantage
is that we may have to adjust things if we change info() to
add automatic newlines, but we can burn that bridge in Mininet
3.x.

examples/multipoll.py

@@ -8,7 +8,7 @@ monitoring them
 
 from mininet.topo import SingleSwitchTopo
 from mininet.net import Mininet
-from mininet.log import setLogLevel
+from mininet.log import info, setLogLevel
 
 from time import time
 from select import poll, POLLIN
@@ -55,7 +55,7 @@ def monitorTest( N=3, seconds=3 ):
     net = Mininet( topo )
     net.start()
     hosts = net.hosts
-    print( "Starting test..." )
+    info( "Starting test...\n" )
     server = hosts[ 0 ]
     outfiles, errfiles = {}, {}
     for h in hosts:
@@ -69,10 +69,10 @@ def monitorTest( N=3, seconds=3 ):
                    '>', outfiles[ h ],
                    '2>', errfiles[ h ],
                    '&' )
-    print( "Monitoring output for", seconds, "seconds" )
+    info( "Monitoring output for", seconds, "seconds\n" )
     for h, line in monitorFiles( outfiles, seconds, timeoutms=500 ):
         if h:
-            print( '%s: %s' % ( h.name, line ) )
+            info( '%s: %s\n' % ( h.name, line ) )
     for h in hosts:
         h.cmd('kill %ping')
     net.stop()