Adding python 3.3 to test environment, mani fixes

Added python 3.3 to test-suite

Removed unused import

Removed unused import

Migrated to EAFP for attribute checking

Bumped version of ModulePickling for migration to hashlib

Added py33 environment to tox

Fixed issue with package importing on python 3.3

jedi/imports.py

@@ -5,9 +5,8 @@ any actual importing done. This module is about finding modules in the
 filesystem. This can be quite tricky sometimes, because Python imports are not
 always that simple.
 
-Currently the import process uses ``imp`` to find modules. In the future, it's
-a goal to use ``importlib`` for this purpose. There's a `pull request
-<https://github.com/davidhalter/jedi/pull/109>`_ for that.
+This module uses imp for python up to 3.2 and importlib for python 3.3 on; the
+correct implementation is delegated to _compatibility.
 
 This module also supports import autocompletion, which means to complete
 statements like ``from datetim`` (curser at the end would return ``datetime``).
@@ -17,7 +16,6 @@ from __future__ import with_statement
 
 import os
 import pkgutil
-import imp
 import sys
 import itertools