First crack at Python 3 compatibility

Mostly we just use mininet.util.pexpect so that we can use
unicode strings without changing calls to pexpect.spawn()

examples/test/test_bind.py

@@ -5,7 +5,7 @@ Tests for bind.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testBind( unittest.TestCase ):
 

examples/test/test_clusterSanity.py

@@ -5,7 +5,7 @@ A simple sanity check test for cluster edition
 '''
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class clusterSanityCheck( unittest.TestCase ):
 

examples/test/test_controllers.py

@@ -5,7 +5,7 @@ Tests for controllers.py and controllers2.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testControllers( unittest.TestCase ):
 

examples/test/test_controlnet.py

@@ -5,7 +5,7 @@ Test for controlnet.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testControlNet( unittest.TestCase ):
 

examples/test/test_cpu.py

@@ -15,7 +15,7 @@ cfs	10%	1.29e+09
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 import sys
 
 class testCPU( unittest.TestCase ):

examples/test/test_emptynet.py

@@ -5,7 +5,7 @@ Test for emptynet.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testEmptyNet( unittest.TestCase ):
 

examples/test/test_hwintf.py

@@ -7,7 +7,7 @@ Test for hwintf.py
 import unittest
 import re
 
-import pexpect
+from mininet.util import pexpect
 
 from mininet.log import setLogLevel
 from mininet.node import Node

examples/test/test_intfoptions.py

@@ -5,7 +5,7 @@ Test for intfOptions.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 import sys
 
 class testIntfOptions( unittest.TestCase ):

examples/test/test_limit.py

@@ -5,7 +5,7 @@ Test for limit.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 import sys
 
 class testLimit( unittest.TestCase ):

examples/test/test_linearbandwidth.py

@@ -5,7 +5,7 @@ Test for linearbandwidth.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 import sys
 
 class testLinearBandwidth( unittest.TestCase ):

examples/test/test_linuxrouter.py

@@ -5,7 +5,7 @@ Test for linuxrouter.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 from mininet.util import quietRun
 
 class testLinuxRouter( unittest.TestCase ):

examples/test/test_multilink.py

@@ -6,7 +6,7 @@ validates mininet interfaces against systems interfaces
 '''
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testMultiLink( unittest.TestCase ):
 

examples/test/test_multiping.py

@@ -5,7 +5,7 @@ Test for multiping.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 from collections import defaultdict
 
 class testMultiPing( unittest.TestCase ):

examples/test/test_multipoll.py

@@ -5,7 +5,7 @@ Test for multipoll.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testMultiPoll( unittest.TestCase ):
 

examples/test/test_multitest.py

@@ -5,7 +5,7 @@ Test for multitest.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testMultiTest( unittest.TestCase ):
 

examples/test/test_nat.py

@@ -5,7 +5,7 @@ Test for nat.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 from mininet.util import quietRun
 
 destIP = '8.8.8.8' # Google DNS

examples/test/test_natnet.py

@@ -5,7 +5,7 @@ Test for natnet.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 from mininet.util import quietRun
 
 class testNATNet( unittest.TestCase ):

examples/test/test_numberedports.py

@@ -5,7 +5,7 @@ Test for numberedports.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 from collections import defaultdict
 from mininet.node import OVSSwitch
 

examples/test/test_popen.py

@@ -5,7 +5,7 @@ Test for popen.py and popenpoll.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testPopen( unittest.TestCase ):
 

examples/test/test_scratchnet.py

@@ -5,7 +5,7 @@ Test for scratchnet.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 
 class testScratchNet( unittest.TestCase ):
 

examples/test/test_simpleperf.py

@@ -5,7 +5,7 @@ Test for simpleperf.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 import sys
 from mininet.log import setLogLevel
 

examples/test/test_sshd.py

@@ -5,7 +5,7 @@ Test for sshd.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 from mininet.clean import sh
 
 class testSSHD( unittest.TestCase ):

examples/test/test_tree1024.py

@@ -5,7 +5,7 @@ Test for tree1024.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 import sys
 
 class testTree1024( unittest.TestCase ):

examples/test/test_treeping64.py

@@ -5,7 +5,7 @@ Test for treeping64.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 import sys
 
 class testTreePing64( unittest.TestCase ):

examples/test/test_vlanhost.py

@@ -5,7 +5,7 @@ Test for vlanhost.py
 """
 
 import unittest
-import pexpect
+from mininet.util import pexpect
 import sys
 from mininet.util import quietRun