Compatibility for Python 3.

Under Python 3, the 'new' module for creating classes is no longer
present. Instead this operation is in the 'types' module.

Timer.py

@@ -4,10 +4,18 @@ Timer management for setting arbitrary timeouts on OSX and Linux.
 """
 
 import os
-import new
 import signal
 import time
 
+try:
+    # Python 2 can use the 'new' module
+    import new
+    new_class = new.classobj
+except ImportError:
+    # Python 3 must use the 'types' module
+    import types
+    new_class = types.new_class
+
 from functools import total_ordering
 
 
@@ -246,7 +254,7 @@ class Timer(object):
         self.start_time = None
         self.end_time = None
         if self.timeout_in_seconds:
-            self.exception = new.classobj('Timeout_%s' % (self.idname,), (TimerTimeout,), {})
+            self.exception = new_class('Timeout_%s' % (self.idname,), (TimerTimeout,), {})
         else:
             self.exception = TimerTimeout
         self.alarm = None