Fix ImportError if sqlalchemy not installed

If sqlalchemy isn't installed, this would try to import the sqlalchemy
wrapper and then kick up an ImportError.

This changes it so that if there's an ImportError, it gets ignored.
Merge pull request #19 from willkg/sqlalchemy-fix

Fix ImportError if sqlalchemy not installed
No set comprehensions in python 2.6 :(
Replace assertGreaterEqual with assertTrue(a >= b)
Merge pull request #26 from iankronquist/py26-fixes

Py26 fixes
Add an iter_entry_points style test

It's broken, but should wind up in source control in case we ever return to
using entry points
Add tests for the Spicedham object's methods
Rename the tests
Clean up tests

Make them somewhat clearer and simpler.
Flake8 fixes
Add nose to requirements & specify Django version
Explain how to run tests in the README
Add mock the requirements
Python 2.6 fixes
Merge branch 'tests' of github.com:iankronquist/spicedham into tests

Conflicts:
	requirements.txt
	tests/test_spicedham.py