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/parsing_representation.py

@@ -560,8 +560,10 @@ class Flow(Scope):
     @parent.setter
     def parent(self, value):
         self._parent = value
-        if hasattr(self, "next") and self.next:
+        try:
             self.next.parent = value
+        except AttributeError:
+            return
 
     def get_code(self, first_indent=False, indention='    '):
         stmts = []