Fix syntax errors cause by old octal literals
Use new urllib.parse imports with fallbacks
Replace old except syntax with new one

Drops Python 2.5 support
Remove basestring, unicode from code base
Handle Python 3 keys/values iterators
Turn ResultIter class into Python 3 iterator
Move from sqlalchemy-migrate to alembic

This affects how columns are added and dropped from
tables. MetaData and SQLATable objects have to be
recreated to make sync changed columns.
Add Py 2 and Py 3 classifiers
Replace unicode with str, duck type encode
Fix a couple of more iterator changes
Put actual unicode character into test data
Make argparse a Python 2.6 dependency
Fix Python version detection for Python 2.6
Fix tests under Python 2.6

assertRaises is not a context manager under Py 2.6
Merge branch 'python-3' of github.com:stefanw/dataset into stefanw-python-3
fix test for ordereddicts