use unittest2, so tests run under py2.6

req.txt

@@ -1,3 +1,4 @@
 nose
 coverage
+unittest2
 mox3

tests/test_IS.py

@@ -1,4 +1,4 @@
-import unittest
+import unittest2 as unittest
 import socket
 import sys
 import os

tests/test_base91.py

@@ -1,4 +1,4 @@
-import unittest
+import unittest2 as unittest
 import sys
 
 from aprslib import base91

tests/test_exceptions.py

@@ -1,4 +1,4 @@
-import unittest
+import unittest2 as unittest
 
 from aprslib.exceptions import *
 

tests/test_parse.py

@@ -1,7 +1,7 @@
 # encoding: utf-8
 
 import sys
-import unittest
+import unittest2 as unittest
 from mox3 import mox
 
 from aprslib import parse

tests/test_parse_comment_telemetry.py

@@ -1,4 +1,4 @@
-import unittest
+import unittest2 as unittest
 
 from aprslib.parsing import _parse_comment_telemetry
 from aprslib import base91

tests/test_parse_header.py

@@ -1,4 +1,4 @@
-import unittest
+import unittest2 as unittest
 import string
 from random import randint, randrange, sample
 

tests/test_passcode.py

@@ -1,4 +1,4 @@
-import unittest
+import unittest2 as unittest
 from aprslib import passcode