TST: Attempt to import unittest2 if running python 2.6
TST: Enable Travis CI for Python 2.6
BUG: Everybody likes dictionary comprehensions. Except Python 2.6.
TST: Clean up tests with assertRaises context manager.
TST: Separate python 2.6 requirements for Travis CI and add ordereddict
TST: pip install, don't source, the 2.6 requirements
BUG: OrderedDict is not in collections module in python 2.6
BUG: format statements need a position in python 2.6
TST: unittest2 didn't like skipIf
TST: Use local unittest for python 2.6 compatability in test_geocode
Revert "TST: unittest2 didn't like skipIf"

This reverts commit e70ea78321749b8229fdfd1b359b050af1c25a34.
TST: Use local unittest for python 2.6 compatability in test_types
TST: Explicitly use relative imports and clean up tests
DOC: Update docs to list supported python versions