Removed Transaction.py. The new transaction package takes its place.

get_transaction() is still stuffed into __builtin__ as a magical side
effect of importing ZODB.

src/ZODB/__init__.py

@@ -15,11 +15,16 @@
 __version__ = "3.3a2"
 
 import sys
+import __builtin__
 
 from persistent import TimeStamp
 from DB import DB
-import Transaction
+from transaction import get as get_transaction
 
 # Backward compat for old imports. I don't think TimeStamp should
-# really be in persistent anyway
+# really be in persistent anyway.
 sys.modules['ZODB.TimeStamp'] = sys.modules['persistent.TimeStamp']
+
+# XXX Issue deprecation warning if this variant is used?
+__builtin__.get_transaction = get_transaction
+del __builtin__

src/ZODB/tests/testPersistentMapping.py

@@ -24,7 +24,7 @@ import unittest
 
 import ZODB
 from ZODB.MappingStorage import MappingStorage
-from ZODB.Transaction import Transaction
+from transaction import Transaction
 import cPickle
 import cStringIO
 import sys